The fastest way to sign a PDF depends on what you already have

You can sign a PDF without special software. If you have Adobe Acrobat Reader (the free version), open the PDF, click "Fill & Sign" in the toolbar, select the pen tool, and draw your signature in the space marked for it. If you don't have Acrobat Reader, you can read it free from Adobe's website.

On a phone or tablet, the built-in tools often work just as well. Apple's Preview app on Mac, Windows' Paint, and Android's built-in markup tools all let you open a PDF, add a signature box, and save the file. Google Drive and Microsoft OneDrive also have free signature features if you upload the PDF there first.

The choice between these options comes down to what's already on your device and whether you want to keep the file on your computer or in the cloud. None of them require you to create an account or pay money.

Key Takeaways

  • Adobe Acrobat Reader's free version has a built-in signature tool that works on Windows, Mac, and mobile devices.
  • Your phone's native apps—Preview on Mac, Paint on Windows, or the markup tool on Android—can sign PDFs without downloading anything extra.
  • Cloud services like Google Drive and Microsoft OneDrive let you upload a PDF, sign it, and read the signed copy without installing software.
  • A typed signature, initials, or a scanned image of your handwritten signature all count as valid signatures for most documents.
  • Always save the signed PDF with a new filename so you keep both the original unsigned version and the signed copy.

Signing with Adobe Acrobat Reader on Windows or Mac

Open the PDF in Adobe Acrobat Reader. Click the "Fill & Sign" button in the right toolbar (it looks like a pen over a document). The toolbar will expand to show signature, initial, and text tools.

Click "Sign" and then click the area where your signature should go. A signature box will appear. You can draw your signature with your mouse or trackpad, type your name, or upload an image of your signature if you've scanned one. Once you're satisfied, click "explore." The signature stays in that spot on the PDF.

To save the signed document, go to File > Save As and give it a new name—something like "contract_signed_2024.pdf"—so you keep the original unsigned version. Acrobat Reader's free version saves the file to your computer.

Signing on an iPhone, iPad, or Mac using Preview and Markup

On a Mac, open the PDF in Preview (the default app for PDFs). Click the Markup toolbar button (it looks like a toolbox) in the top right. Select the signature tool—it's the pen icon. You can draw your signature, or click the + button next to "Signature" to create a new one by signing on your trackpad.

On an iPhone or iPad, open the PDF in the Files app or Mail, tap "Markup" (the pen-in-circle icon), and select the signature tool. Sign on the screen with your finger. Your device will save this signature so you can use it again on future documents without re-signing each time.

After signing, save the file with a new name. On Mac, use File > Export As. On iPhone or iPad, tap "Done" and the changes save automatically to the file you opened.

Signing on Android or Windows using built-in tools

On Android, open the PDF in Google Drive or the Files app. Tap the pencil icon to enter edit mode, then select the drawing or pen tool. Draw your signature directly on the PDF. Save the file when you're done.

On Windows 10 or 11, open the PDF in Microsoft Edge (the default browser). Click the "Draw" tab at the top, select a pen, and draw your signature on the page. Go to File > Save to keep the signed version, or File > Save As to create a new file with a different name.

If you prefer not to use Edge, you can also open the PDF in Paint. Right-click the PDF, select "Open with," and choose Paint. Use the paintbrush tool to add your signature, then save the file.

Using Google Drive or OneDrive if you don't want to install anything

Upload your PDF to Google Drive or OneDrive by dragging it into your browser window or using the "New" or "Upload" button. Right-click the file and select "Open with" > "Google Docs" (for Drive) or "Edit in Browser" (for OneDrive). The PDF will convert to an editable document.

Click "Insert" in the menu, then "Drawing" > "New." Use the drawing tools to create your signature, click "Save and Close," and the signature will appear on the document. read the file back to your computer when you're done.

This method works on any device with a web browser, including phones and tablets. You don't need to install software, and the file stays in your cloud storage until you read it.

Creating a reusable digital signature

If you sign documents regularly, save time by creating one signature you can reuse. On Mac, use Preview's signature feature to save your signature to your device—it will appear in the signature menu on all future documents. On Windows, take a photo or scan of your handwritten signature, save it as an image file, and insert it into PDFs using the Insert menu in Paint or Edge.

In Google Drive or OneDrive, you can draw your signature once in a document, take a screenshot of it, and then insert that image into future PDFs. This avoids having to redraw your signature every time.

Be consistent with how your signature looks across documents. A signature that changes drastically in size or style between documents can raise questions about authenticity, especially on legal or financial paperwork.

What counts as a valid signature on a PDF

A handwritten signature drawn with a mouse, trackpad, or stylus is valid. So is a typed name in a signature field, your initials, or a scanned image of your actual handwritten signature. For most everyday documents—contracts, forms, permission slips—any of these will work.

For legal documents like wills, powers of attorney, or loan agreements, check the specific rules in your state or country. Some jurisdictions require a handwritten signature or a certified digital signature, while others accept typed names or initials. When in doubt, ask the person or organization requesting the signature what format they need.

Always keep a copy of the signed PDF for your records. Save it with a date in the filename so you can find it later if questions come up about when you signed it.

Frequently Asked Questions

Can I sign a PDF on my phone without downloading an app?

Yes. Upload the PDF to Google Drive or OneDrive, open it in your browser, and use the drawing tools to add your signature. You can also use your phone's built-in markup tool if you open the PDF in the Files app or Mail.

Is a typed name as valid as a handwritten signature?

For most documents, yes. For legal paperwork like contracts or wills, check your local rules—some places require a handwritten signature. When in doubt, ask whoever is requesting the signature what format they accept.

What if I make a mistake while signing?

Undo the signature (Ctrl+Z on Windows, Command+Z on Mac) and try again. If you've already saved the file, open it again and add a new signature in the correct spot, then save it with a new filename.

Can I use the same signature on every document?

Yes. Save your signature as an image or use your device's built-in signature feature to store it. Most apps will let you reuse it without redrawing it each time.

Do I need special software to sign a PDF legally?

No. A PDF signed with any of these free tools is legally valid for most purposes. Only specialized documents like notarized papers or certain financial contracts may require certified digital signatures, which do need special software.