How to sign a PDF

How to sign a PDF electronically: the short answer

To sign a PDF document electronically (eSign it) for free, open it in a PDF app, create your signature once (draw, type or photograph it) and place it on the signature line. No printing, and the tools are already on most devices:

• Mac: Preview, Markup toolbar > Sign.
• Windows: Adobe Acrobat Reader, All tools > Fill & Sign.
• iPhone and iPad: Markup in Files or Mail, + > Add Signature.
• Android: the Acrobat Reader app.

Each adds a simple electronic signature (SES), fine for most everyday documents. If others must sign too, or you need proof of who signed, use an eSignature platform.

How to sign a PDF for free

You can sign a PDF for free in three ways:

• On your device: Preview on Mac, Adobe Acrobat Reader on Windows and Android, and Markup on iPhone and iPad are all free. Steps for each are below.
• Online, in your browser: make your signature in our free signature generator, add the signature to the PDF, then lock it into the page with Flatten PDF.
• With other signers: fynk’s Free plan lets you send a PDF for signature and get it back signed, with an audit trail.

How to sign a PDF on Mac (Preview)

Preview, built into macOS, signs PDFs with no extra software. These steps work on current macOS, including Sequoia 15 and Tahoe 26.

1. Open the PDF in Preview. If another app opens, Control-click the file and choose Open With > Preview.
2. Show the Markup toolbar: click the pen-tip icon at the top of the window.
3. Click Sign and pick a saved signature, or create one:
   • Trackpad: sign with your finger, press any key, click Done.
   • Camera: sign on white paper, hold it up to the camera, click Done. The easiest way to reuse your handwritten signature.
   • iPhone or iPad: click Select Device and sign with your finger or Apple Pencil.
4. Place it: drag the signature to the line and resize it with the handles.
5. Save with File > Save. To keep the unsigned original, use File > Duplicate first.

With iCloud Drive on, your signatures sync to your other Macs. Prefer Acrobat? The Windows steps below work the same on Mac.

How to sign a PDF on Windows (Adobe Acrobat Reader or Edge)

Windows has no built-in tool like Preview, so use the free Adobe Acrobat Reader:

1. Open the PDF in Acrobat Reader.
2. Select All tools > Fill & Sign.
3. Create your signature: Type your name, Draw it, or upload an Image (our signature generator makes a clean PNG). Select Apply.
4. Place it on the line and resize it.
5. Save the signed PDF, ideally as a copy.

No Acrobat? Microsoft Edge lets you draw on a PDF with ink: open the PDF, select Draw, sign and save. It does not store your signature.

If the PDF started as a Word file, sign the Word document before exporting. For a spreadsheet, sign the Excel file or sign in Google Sheets first. Writing in Google Docs? Insert your signature in Google Docs and download the file as a PDF.

How to sign a PDF on iPhone and iPad

To sign a PDF on iPhone, open it in the Files app or Mail, tap the Markup button, then + > Add Signature, sign with your finger and tap Done. Nothing to install, and the same works on iPad.

1. Open the PDF in Files, or tap the attachment in Mail.
2. Tap Markup (the pen-tip icon), then + > Add Signature.
3. Sign with your finger or Apple Pencil and tap Done, or pick a saved signature.
4. Drag it into place, resize it, and tap Done.

From Mail, a reply with the signed PDF opens straight away. In Files, signing overwrites the file, so touch and hold it and tap Duplicate first to keep the original. Since iOS 26 and iPadOS 26, Apple’s Preview app also signs PDF forms.

How to sign a PDF on Android

Android has no standard built-in signing tool, so use the free Adobe Acrobat Reader app:

1. Install Acrobat Reader from Google Play and open the PDF.
2. Open the fill and sign tools and add a signature.
3. Draw it with your finger and confirm.
4. Tap where it goes, resize it, and save or share the PDF.

How to digitally sign a PDF (with a certificate)

Electronically signing adds an image of your signature. Digitally signing adds a certificate (a digital ID) that seals the file, so any later change shows up. It is the only way to reach an advanced or qualified level in a PDF reader. In Adobe Acrobat Reader:

1. Select All tools > Use a certificate, then Digitally sign.
2. Drag a rectangle where the visible signature should appear.
3. In the Sign with a Digital ID dialog, choose your digital ID, or create one there.
4. Enter its password or PIN. Tick Lock document after signing if nobody should change the file.
5. Select Sign and save.

A self-made Acrobat ID proves the file is unchanged, not who you are. For an advanced electronic signature (AES) or qualified electronic signature (QES) you need a certificate from a trust service provider. These signatures follow the PAdES standard, which validators across the EU can check.

How to sign a PDF contract with other people

To sign a PDF contract, everyone must sign the same final version, with a signature level the contract allows, and you need one signed copy with a record of who signed and when. Emailing a PDF back and forth gives you several copies and no such proof. Check two things first:

• The level: most commercial contracts only need the simplest of the three types of electronic signatures. In the EU, written form needs a qualified one, and the rules for legally binding e-signatures differ by country.
• Who signs: each person signing for a company needs the authority to sign.

With fynk’s e-signatures it takes three steps, and it is included in the Free plan:

1. Sign in to fynk.
2. Drag and drop your PDF.
3. Sign it, or send it to the other signers. Choose SES, AES with a phone code or a national eID, or QES; fynk sends reminders, keeps an audit trail and stores the signed contract in your contract repository.

Frequently asked questions

• Can I sign a PDF without printing it?

  Yes. Open the PDF in Preview on a Mac, Acrobat Reader on Windows, Mac or Android, or Markup on iPhone and iPad. Draw, type or photograph your signature, place it on the page, save and send the file back. No printer or scanner needed.

• Why won't my PDF let me sign?

  Usually the PDF is password-protected or restricted, already digitally signed and locked, or its signature field expects a certificate-based digital signature, not an image. Check the document properties for security settings. If you know the password, Unlock PDF removes it or the editing restrictions in your browser; otherwise ask the sender for an unlocked version.

• How do I add a handwritten signature to a PDF?

  Sign on white paper and capture it: in Preview on a Mac, hold the paper up to the camera; in Acrobat Reader, upload a photo or scan as an image. You can also draw it with a trackpad, mouse, finger or stylus. A transparent PNG of your signature works in any PDF editor.

• How to sign PDF documents sent by email?

  Download the attachment, open it in Preview on a Mac or Acrobat Reader on Windows or Android, sign, save, and reply with the signed file attached. On iPhone and iPad you can sign straight from Mail: tap the PDF, tap Markup, sign and tap Done, and Mail opens a reply with the signed PDF.

• How do I flatten a signed PDF?

  Drop the signed file into our free Flatten PDF tool and download the flattened copy. It merges the signature and form fields into the page so they can no longer be moved or edited, and the file never leaves your browser. Printing to a new PDF does the same. Never flatten a PDF with a certificate-based digital signature: it breaks the seal and the signature shows as invalid.

• What is a free app for filling and signing documents?

  Adobe Acrobat Reader is free on Windows, Mac, iPhone, iPad and Android and fills in forms and adds your signature. Preview on a Mac and Markup on iPhone and iPad do the same with nothing to install. To collect signatures from other people, fynk's Free plan includes sending PDFs for signature.

• How to create an electronic signature?

  Draw it with a mouse, trackpad or finger, type your name, or photograph your signature on paper. Most PDF apps offer this when you first add a signature. For a clean, reusable image, our free signature generator creates a transparent PNG. For contracts that need proof of who signed, use an eSignature platform that verifies the signer.