Sign a PDF on your computer using your phone
Signing with a mouse or a trackpad rarely looks like your real signature. If the document is on your computer, you can use your phone as a signing pad instead: scan a code, sign with your finger, and the signature appears on the computer a moment later.
Updated October 23, 2026 · 2 min read
How it works
The PDF stays on your computer the whole time. Your phone is only used to draw. When you open the signature box on a computer, PDF Tools shows a QR code right next to the drawing pad, so you can choose between the mouse and your phone without looking for an extra button.
You don’t need to install anything on the phone. Its camera and browser are enough, and the phone and the computer don’t need to be on the same Wi-Fi. Both just need an internet connection.
Step by step
- 1On your computer, open Sign PDF and choose your PDF. It opens in the studio, ready to sign.
- 2Click Signature (or Initials). Beside the drawing pad you’ll see Or sign on your phone and a QR code.
- 3Point your phone’s camera at the code and open the link it shows.
- 4On the phone, the page Sign on this phone opens. The computer now says the phone is connected.
- 5Draw your signature with your finger and tap Send to computer.
- 6On the computer, the signature arrives and is placed on the page. Drag it into position and resize it with its corner handle.
- 7Click Apply, then Download. Your file is saved with “signed” added to its name.
What travels, and what doesn’t
Only the drawing of your signature travels. The PDF itself never leaves the computer. On the phone, the signature is encrypted before it is sent, using a key that is part of the QR code and is never sent to our server.
Our server only passes the encrypted signature from the phone to the computer, without being able to read it. Only the computer that showed the code can open it. Each code works for 10 minutes and delivers one signature. If nobody scans a code in time, the computer quietly replaces it with a fresh one. If it expired after you scanned it, click New code.
If the code won’t scan
- Most phone cameras read QR codes on their own. If yours doesn’t, try your phone’s QR scanner or a camera app that supports codes.
- Turn up the brightness of your computer screen and hold the phone a little further away.
- Use Copy link under the code and open the link on your phone another way, for example by sending it to yourself. Keep that link to yourself: it is what lets a phone send a signature to your computer.
- Keep the PDF Tools page open on the computer until the signature arrives.
Reuse it next time
Leave Save for next time ticked in the signature box, and the signature that came from your phone is kept in this computer’s browser. Next time you open the signature box, it is waiting on the Saved tab, and you won’t need your phone at all.
Questions
Do I need to install an app on my phone?
No. The phone’s camera opens a normal web page in its browser, and that is all you need to sign.
Do my phone and computer need to be on the same Wi-Fi?
No. Each one only needs an internet connection. Mobile data on the phone is fine.
Can PDF Tools see my signature?
No. The signature is encrypted on your phone with a key that never reaches our server, and only the computer that showed the code can read it. The encrypted copy is kept for no more than 10 minutes.
Why don’t I see a QR code on my phone or tablet?
On a touch screen you can sign directly with your finger, so the code is only offered on computers.
Try it now
Free, in your browser, and your files stay on your device.