How to sign a PDF for free, and when a drawn signature isn't enough
Learn how to sign a PDF for free in Preview, Edge, Chrome, Firefox or Acrobat Reader, when you need a digital ID, and how to get others to sign it too.
Sign a document and check the record yourself.
Start nowHow to sign a PDF: the short answer
How to sign a PDF depends on what the signature has to do. For a form you just need to send back, open it in a tool you already have and draw your name: Preview on a Mac, or Edge, Chrome or Firefox on any computer. Adobe Acrobat Reader does the same and is free. Each of them puts a picture of your signature on the page.
Two cases need more. If you're asked to digitally sign the PDF or to use a certificate, you sign with a digital ID in Adobe Acrobat. And if other people have to sign the same file, a signing service such as Chaindoc's document signing sends it out, collects every signature and records who signed and when.
The steps for each method are below, with a table of what each one actually proves.
Every way to sign a PDF, and what each one proves
| Method | Cost | Works on | What you get | What it proves |
|---|---|---|---|---|
Preview | Free, built into macOS | Mac | A signature from trackpad, camera or iPhone, saved for reuse | That someone placed this mark on this copy |
Microsoft Edge | Free, built into the browser | Windows and macOS | Ink drawn with a mouse, pen or finger | The same |
Google Chrome | Free | Any computer with Chrome | A pen drawing, plus typed text | The same |
Firefox | Free | Any computer with Firefox | A typed, drawn or image signature, saved for reuse | The same |
Acrobat Reader (Fill & Sign) | Free download | Windows and macOS | A typed, drawn or image signature, or initials | The same |
Acrobat with a digital ID | Acrobat, plus a self-signed or issued digital ID | Windows and macOS | A certificate-based digital signature | Which certificate signed, and whether the file changed after signing |
Chaindoc (signing service) | Free plan: 5 signatures a month, no card | Any browser | A PDF signed by everyone, plus a certificate of completion | Who was invited, when each person signed, and the exact version, whose hash is recorded on the SKALE network |
Electronic, digital or drawn: which signature your PDF needs
People search for how to sign a PDF document, how to electronically sign a PDF and how to digitally sign a PDF as if they were one thing. Often they are. Sometimes they aren't, and that decides which part of this guide you need.
- A drawn or typed signature. This is an electronic signature in the everyday sense. Preview, the browsers and Acrobat Reader all make one: an image or an ink stroke sitting on the page.
- A certificate-based digital signature, the strict meaning Adobe gives the word "digital". Acrobat binds your digital ID to the file, so anyone who opens it later can see whether it was changed after you signed.
- A signing-service record. Each person signs through their own emailed link, and the service keeps the evidence: who was invited, when they signed, which version.
How do you tell which one you've been asked for? Read the request. "Sign and return" usually means a drawing is fine. "Digitally sign", "use your certificate" or a named national eID means the second. A contract between several people is the third, whatever the email calls it. Can't tell? Ask before you sign.
How to sign a PDF on a Mac with Preview
Preview is the PDF app built into macOS, so nothing needs installing. These steps follow Apple's Preview User Guide.
Open the PDF in Preview
Double-click the file. If another app opens it, Control-click the file and choose Open With > Preview.
Show the Markup toolbar and click Sign
Click the Show Markup Toolbar button if the toolbar isn't showing, then click the Sign button.
Create your signature
Pick one of three ways: sign on the trackpad with a finger, hold a signature written on white paper up to the built-in camera, or choose Select Device and sign on a nearby iPhone or iPad.
Place and size it
Click the signature, drag it onto the signature line, then use the handles to adjust its size.
Save the file
Choose File > Save. To keep an unsigned original, duplicate the file before you sign.
That's how to sign a PDF on Mac with nothing to install. Preview remembers your signatures, and with iCloud Drive turned on they appear on your other Macs too. To delete one, click Sign, point at it and click the X.
Use the camera for anything a client will see
A signature drawn with one finger on a trackpad rarely looks like the one you write in ink. The camera option fixes that: sign white paper with a dark pen and hold it up so the signature sits on the blue line, as Apple's Preview User Guide shows. Do it once, in good light.
Preview's camera option turns a signature written in ink into one you can reuse on every PDF.
How to sign a PDF on Windows in Edge, Chrome or Firefox
Windows has no Preview, so how to sign a PDF on Windows comes down to the browser. Edge ships with Windows, and Chrome and Firefox now have signing tools in their PDF viewers. The steps are close enough to share one list, on any operating system.
Open the PDF in the browser
Drag the file into a browser window, or right-click it and choose Open with.
Pick the signing tool
In Edge, click Draw. In Chrome, select Draw, then Pen. In Firefox, click Add signature, then + Add New Signature.
Sign
Use a mouse, a touchscreen or a stylus. Firefox also lets you type your name or insert an image of your signature instead.
Set the pen and fix mistakes
Edge and Chrome let you change the ink color and thickness; a thin dark line looks most like ink. Both have an eraser, and in Firefox, Clear signature starts over before you add it.
Save a signed copy
In Edge, click Save. In Chrome, choose Download, then With your changes. In Firefox, click Save. Open the saved file once to check the signature is really in it.
Firefox keeps a signature for reuse if you tick Save signature. In Chrome you draw it each time.
A drawn signature carries no proof of who drew it
Mozilla says it plainly on its Firefox PDF viewer help page: signatures added there are "simple annotations" with no authentication or verification. The same goes for Edge, Chrome, Preview and Fill & Sign. That doesn't make them worthless: US law accepts a mark you adopt with intent to sign. But the file can't tell anyone who placed the mark or when.
How to sign a PDF in Adobe Acrobat Reader for free
Acrobat Reader is the free Adobe app many offices assume you have. Its signing feature is called Fill & Sign.
Open the PDF in Acrobat Reader
If the PDF has form fields, Reader detects them, so type your name and the date first.
Start Fill & Sign
Click the Sign icon in the toolbar, or choose Tools > Fill & Sign.
Choose a signature or initials
Signatures you've added before appear as options. Pick one and skip to step 5.
Create it
Type your name and pick a style, draw it, or choose Image to import a photo or scan of your signature. Tick Save Signature while signed in and Adobe keeps it for next time.
Apply and place it
Click Apply, then click where the signature goes. Move it with the arrow keys; resize or delete it from the field's toolbar.
Save the file
When you save, the signature and any text you typed become part of the PDF.
That's how to add a signature to a PDF in Adobe's free app. Asking other people to sign through Adobe may need a paid Acrobat plan, Adobe's own page says.
Adobe's online tool asks you to sign in
Rather not install Reader? Adobe's Sign PDF tool lets you sign a PDF online: upload the file, type, draw or upload your signature, click Next. Two catches, both stated on Adobe's page: you must be signed in to complete the form, and an uploaded file is deleted unless you sign in to save it. So it's free, but you'll need an Adobe account.
How to digitally sign a PDF with a certificate
A certificate-based signature needs a digital ID: a certificate plus a private key protected by a password. Adobe's help page for Acrobat on the desktop gives these steps.
Open the certificate tools
Select All tools, then Use a certificate.
Choose Digitally sign
Click OK on the instructions, then drag a rectangle where the signature should appear.
Pick your digital ID
Select it and click Continue. No ID yet? Choose Configure New Digital ID: you can use a signature device, import an ID file or create a self-signed one.
Check the details and enter the password
Acrobat shows how the signature will look. Type your digital ID password.
Decide whether to lock the file
Tick Lock document after signing if nobody should change the PDF afterwards.
Sign and save
Select Sign, choose where to save, and save. The signature panel then confirms the signatures are valid.
Where the ID comes from matters more than the clicks. Adobe notes that IDs issued by trusted providers, such as governments, banks and trust service providers, carry more weight than a self-signed ID, which some recipients won't accept.
After a digital signature, leave the file alone
Signing is the step you can't take back. Once a PDF carries a certificate signature, later changes show up in the signature panel as a modified document, and printing it to a new PDF drops the digital signature completely. So fill in every field first, sign last, and keep the signed file exactly as it is. If something's wrong, fix the source and sign a fresh copy.
How to get a PDF signed by someone else
The tools above are built for one person on one device. When a client or a landlord has to sign the same PDF, emailing it back and forth leaves several copies and no record of who signed which. Here's how a signing service runs the round, using Chaindoc.
Upload the PDF
Chaindoc computes the file's hash on upload: a fingerprint that changes if a single byte does.
Place the signature fields
Put a field wherever each person has to sign.
Add the signers
Enter up to 10 email addresses per request. Everyone is invited at once; a fixed signing order is available through approval routes on the Business plan.
Publish and send
The document's version hash is recorded on the SKALE network when you publish, and each signer gets a link by email.
Follow the status
Chaindoc sends reminders to anyone who hasn't signed yet. If you need to verify a signer's identity, an ID check (KYC) is an optional extra on the paid plans.
Download the signed PDF
When the last person signs, each signer's proof is recorded on the blockchain and you get a certificate of completion listing the signers, the times and the document hash.
The Free plan covers 5 signatures a month and doesn't ask for a credit card.
Need someone else's signature on that PDF?
Upload it to Chaindoc, add up to 10 signers and follow each signature to the end, with a certificate of completion and a blockchain record. Free plan: 5 signatures a month, no card.
Send a PDF for signingSigning a PDF on your phone
Phones have their own tools. On an iPhone or iPad, open the PDF, tap Markup and add your signature. On Android, the Google Drive app lets you annotate a PDF with a pen. The full steps, and their catches, are in our guide to signing documents on a phone.
Got a Chaindoc signing request on your phone? The link opens in the phone's browser, so there's nothing to install.
Is a signed PDF legally binding?
In the US, usually yes. Section 101(a) of the federal ESIGN Act says a signature or contract "may not be denied legal effect, validity, or enforceability solely because it is in electronic form." Section 106(5) defines an electronic signature broadly: a sound, symbol or process attached to a record and adopted by a person with the intent to sign it. A signature you draw in Preview or a browser fits, as long as you meant to sign. So if all you need is how to sign a PDF electronically for an ordinary US contract, any method above can do it.
States add the Uniform Electronic Transactions Act (UETA), which each state enacts on its own. And where a law says a record must be kept, section 101(d) accepts an electronic copy that stays accurate and can be reproduced later, so keep the signed PDF unedited, somewhere you'll still be able to open it in years.
What ESIGN leaves out
The general rule has exceptions. Section 103 leaves out, among others:
- wills, codicils and testamentary trusts
- adoption, divorce and other family-law matters
- court orders, notices and official court documents
- notices of utility shutoff, or of default, foreclosure, repossession or eviction on a primary residence
- cancellation of health or life insurance, and recall notices for products that put health or safety at risk
In the EU
Article 25(1) of eIDAS says an electronic signature can't be refused legal effect, or admission as evidence, just because it's electronic or isn't qualified. Article 25(2) gives a qualified electronic signature the same legal effect as a handwritten one. Chaindoc can run that qualified signing flow with your own national eID or certificate provider, and applies the signature in the PAdES-BES format; Chaindoc isn't a trust service provider and doesn't issue the certificate. Our explainer on digital vs electronic signatures sorts out the terms.
So the law seldom asks whether a drawn signature counts. The harder question comes later, in a dispute: can you show who drew it? A picture on a page can't answer that. A certificate or a signing record can.
How to check a signed PDF
What you can check depends on what's in the file.
A certificate-based signature can be validated. Acrobat shows it in the signature panel, and Microsoft Edge's PDF reader can view and validate certificate signatures as well. For a detailed report, Chaindoc's PDF signature verification service takes a file of up to 50 MB: you confirm your email with a one-time code, and it reports on integrity, the signing certificate and its chain, revocation, timestamps and the PAdES profile, each with a pass or fail. Chaindoc says the PDF isn't stored after the check.
A drawn signature can't be validated at all. There's no certificate in it to test. For a document signed through Chaindoc, the evidence is the certificate of completion and the matching records on the SKALE network.
Acrobat sometimes reports a valid signature as unknown; our guide explains how to fix "signature validity is unknown".
Mistakes to avoid when you sign a PDF
Most second rounds of signing come from a handful of slips:
- 1.Signing before filling. Type the date and your details first. In a certificate-signed file, every later edit shows.
- 2.Saving the wrong copy. Chrome asks whether to download the PDF with or without your changes, as Google's Chrome help page describes. Pick the wrong one and the signature isn't in the file.
- 3.A signature image with a white box around it. Use a transparent PNG, like the one our signature generator exports, or Acrobat's Image option with a clean scan.
- 4.Signing the version from three emails ago. When several people pass a PDF around, someone signs an old copy. One shared signing request ends that.
- 5.Flattening a digitally signed file. Printing it to PDF bakes the marks into the page and drops the certificate signature along with them.
- 6.Leaving your signature image in a shared folder. Anyone who can copy it can paste it onto another document.
Which way to sign a PDF should you use?
For your own paperwork, say a lease renewal, a school form or a one-page consent, use whatever's built in: Preview on a Mac, the browser on Windows, Acrobat Reader if your office expects it. Knowing how to sign a PDF this way saves you a printer and a scanner.
When someone asks for a digital signature or a certificate, a drawing won't pass. Get a digital ID and sign in Acrobat, or use the qualified flow your national eID supports.
And when the PDF needs more than one signature, stop emailing it around. Send it through a signing service and keep the record. In Chaindoc you can draft the contract from a template and send it for signing in the same place, then file the certificate of completion next to the PDF.
Honestly, the signing is the easy part. Knowing which kind the other side expects is harder, so ask first.
Sources checked for this guide
We read the help pages and the ESIGN Act text on October 14, 2026. Where a vendor dates its page, that date is given as well, because app menus change between versions.
- 1.Fill out and sign PDF forms in Preview on Mac · Apple SupportMarkup toolbar, Sign button, trackpad, camera and iPhone or iPad options, iCloud Drive sync; checked 2026-10-14
- 2.PDF reader in Microsoft Edge · Microsoft LearnInking to sign, ink color and width, viewing and validating certificate-based signatures; page updated 2026-06-15, checked 2026-10-14
- 3.Manage PDFs in Chrome · Google Chrome HelpDraw > Pen to sign, Eraser, Add text, Download with your changes; checked 2026-10-14
- 4.View and edit PDF files using Firefox's built-in viewer · Mozilla SupportAdd signature with Type, Draw or Image, Save signature, and the note that these are simple annotations; page updated 2026-05-18, checked 2026-10-14
- 5.Sign PDFs in Adobe Acrobat Reader · Adobe HelpFill & Sign steps, signature or initials, Type, Draw or Image, Save Signature; page updated 2026-06-21, checked 2026-10-14
- 6.Add digital signatures to PDFs in Acrobat · Adobe HelpUse a certificate > Digitally sign, Configure New Digital ID, Lock document after signing; page updated 2025-09-23, checked 2026-10-14
- 7.Sign PDF online · AdobeSign-in needed to complete the form and to keep the uploaded file; checked 2026-10-14
- 8.How to digitally sign a PDF · AdobeDigital IDs issued by trusted providers compared with self-signed IDs; checked 2026-10-14
- 9.Electronic Signatures in Global and National Commerce Act, Public Law 106-229 · U.S. Government Publishing Office (govinfo)Sections 101(a), 101(d), 103 and 106(5); checked 2026-10-14
- 10.Electronic Transactions Act · Uniform Law CommissionUETA committee page; checked 2026-10-14
- 11.Regulation (EU) No 910/2014 (eIDAS), consolidated text of 20 May 2024 · EUR-LexArticle 25, legal effects of electronic signatures
Frequently Asked Questions
Answers to popular questions about Chaindoc and secure document workflows.
Use what's already on your computer. On a Mac, Preview's Sign button does it. On Windows or any other system, open the PDF in Edge or Chrome and use the Draw tool, or click Add signature in Firefox, which also takes a typed name or an image. All three are free, and none needs an account.
Every method for a single signer is free: Preview, Edge, Chrome, Firefox and Acrobat Reader cost nothing, though Adobe's online tool needs you to sign in before you can finish. Getting the same PDF signed by other people usually means a signing service. Chaindoc's Free plan covers 5 signatures a month without a credit card.
Signing usually means placing a drawn, typed or image signature on the page. Digitally signing, in Adobe's sense, means applying a certificate-based signature with a digital ID: the file records which certificate signed it and shows if anything changed afterwards. Both can count as electronic signatures in law. Only the second carries evidence inside the file itself, and how much it's worth depends on who issued the ID.
Sign white paper with a dark pen, then scan or photograph it in good light. In Acrobat Reader's Fill & Sign, choose Image; Adobe accepts JPG, PNG, GIF, TIFF and BMP and picks out just the signature from a clean scan. Firefox's Add signature has an Image option too. Or draw one in Chaindoc's signature generator and download a transparent PNG.
Printing it to a new PDF, with Microsoft Print to PDF on Windows or Save as PDF in the Mac print dialog, usually turns a drawn signature into part of the page so it can't be dragged or deleted. Don't do this to a certificate-signed PDF: the printed copy loses the digital signature.
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