The fastest way depends on what you already have

If you have Adobe Acrobat Reader (the free version), you can sign a PDF directly in that program without paying for anything else. Open the PDF, click the "Sign" button in the toolbar, draw or type your signature, and save. If you use Microsoft Word or Google Docs, you can also insert a signature line and sign there before converting to PDF. On a phone, most PDF apps including Adobe Reader, Google Drive, and Apple's built-in tools let you sign by drawing on the screen.

The method that works best for you depends on three things: whether you need a legally binding signature or just a visual one, what software you already have installed, and whether you're signing on a computer or phone. A visual signature (your name written or typed on the document) works for most everyday situations. A legally binding digital signature requires more steps and usually costs money, but creates a tamper-proof record that proves you signed it and when.

Key Takeaways

  • Adobe Acrobat Reader's free version includes a sign tool that works for most PDFs — open the file, click Sign, draw your signature, and save.
  • Google Drive, Microsoft Word, and most phone PDF apps also let you sign by drawing on the screen at no cost.
  • A visual signature (your handwriting or typed name) is enough for contracts, forms, and documents between people who know each other.
  • A legally binding digital signature that creates a tamper-proof record requires software like DocuSign, Adobe Sign, or HelloSign, which charge per signature or per month.
  • On a phone, open the PDF in your device's native app (Apple Files, Google Drive, or Samsung Notes) and look for a pen or markup tool to sign.

Signing in Adobe Acrobat Reader on Windows or Mac

Download Adobe Acrobat Reader from adobe.com if you don't have it. It's free. Open the PDF you want to sign, then look for the "Sign" button in the toolbar on the right side of the screen. Click it.

A menu will appear asking how you want to sign. Choose "Add signature" and then select whether you want to draw your signature with your mouse or trackpad, type your name, or upload an image of your signature. If you draw, use your mouse to write your name in the box that appears. If you type, select a font style and your name will appear in that style. Once you've created your signature, click "Apply" and then click where on the document you want it to appear. Save the file when you're done.

Signing in Google Drive or Google Docs

Open the PDF in Google Drive by uploading it or opening it from your Drive folder. Right-click the file and select "Open with" and then "Google Docs." This converts the PDF to an editable document. Go to the "Insert" menu at the top, then select "Drawing" and then "New." A drawing box will open where you can use your mouse or trackpad to sign your name. Click "Save and close" when you're done, then position the drawing where you want your signature to appear on the page.

When you're finished, download the document back as a PDF. Go to "File," then "Download," then "PDF Document." This gives you a signed PDF you can send or store. This method works on any computer with a web browser and doesn't require you to install software.

Signing on an iPhone or iPad

Open the PDF in the Files app or in Mail if someone sent it to you. Tap the markup button (it looks like a pen tip in a circle) at the bottom right of the screen. Tap the pen icon to draw, then sign your name directly on the document with your finger. You can adjust the pen thickness and color if you want, but the default settings work fine for most signatures.

When you're done signing, tap "Done" and then save the file. If the PDF was sent to you in Mail, you can reply with the signed version directly. If it's in Files, the signature is saved to that file automatically.

Signing on an Android phone

Open the PDF in Google Drive, Google Photos, or your phone's default PDF reader. Look for a pen or markup tool — on most Android phones this is a button that looks like a pen or pencil. Tap it, then draw your signature on the screen with your finger. Some phones let you choose pen color and thickness; the defaults work fine for most documents.

Save the file when you're done. If you're using Google Drive, the changes save automatically. If you're using another app, look for a "Save" or "Done" button to confirm your changes.

When you need a legally binding digital signature

A visual signature (your handwriting or typed name on the document) is legally valid for most everyday documents like contracts between friends, rental agreements, and forms. However, if you need proof that you signed it at a specific time, that the document hasn't been changed since you signed it, or if you're signing something that will be used in court or with a government agency, you need a legally binding digital signature.

Services that provide this include DocuSign, Adobe Sign, HelloSign (owned by Dropbox), and SignNow. These programs create a digital certificate attached to your signature that proves who signed it and when. They cost money — usually between $10 and $40 per month for individuals, or per-signature pricing that ranges from $1.50 to $5 per document. Your bank, employer, or the organization asking you to sign may already have an account with one of these services and can send you a signing link for free.

Troubleshooting common problems

If the Sign button doesn't appear in Adobe Reader, make sure you have the latest version. Go to "Help" and then "Check for Updates." If you're trying to sign a PDF that's locked or protected, you may not be able to add a signature — contact whoever sent you the document and ask them to unlock it or send an unprotected version.

If your signature looks messy or shaky when you draw it with your mouse, try using a touchpad instead, or upload an image of your signature that you've written on paper and photographed. If you're on a phone and the markup tool doesn't appear, try opening the PDF in a different app — Google Drive usually works when the default reader doesn't.

Frequently Asked Questions

Is a signature I draw on a PDF legally valid?

Yes, for most documents. A visual signature (your handwriting or typed name) is legally valid for contracts, agreements, and forms in most situations. However, if you need to prove when you signed it or that the document hasn't been changed, you need a legally binding digital signature from a service like DocuSign or Adobe Sign.

Can I sign a PDF on my phone and send it back?

Yes. Sign the PDF using your phone's markup tool or a PDF app, save it, then email it or send it through whatever method the other person requested. The signed PDF works the same as one signed on a computer.

What if the PDF won't let me add a signature?

The PDF may be locked or protected. Contact the person who sent it and ask them to remove the protection or send an unprotected version. You can also try opening it in a different app — Google Drive sometimes works when Adobe Reader doesn't.

Do I need to buy Adobe Acrobat Pro to sign a PDF?

No. The free version of Adobe Acrobat Reader includes a sign tool. You only need to pay for Adobe Sign if you need legally binding signatures with tamper-proof records, or if you're signing many documents and want advanced features.

Can I use the same signature for every document?

Yes. Once you've created a signature in Adobe Reader or your phone, you can reuse it on other PDFs. The app usually remembers it and offers it as an option the next time you sign something.