asantoolSign a PDF on your phone
A phone is the one device that already has the right input for this: your finger. Open the document, sign it where it needs signing, and send it back — with no app to install and nothing leaving the handset.
Drop the PDF you need to sign
PDFUp to 100 MB · Your files never leave your device4 steps, no waiting.
- 01Add your PDFDrag the file onto the page or pick it from your device. Nothing is uploaded — it opens straight in the browser.
- 02Pinch to find the lineTwo fingers zoom and move the page, so a signature line that is a few pixels wide becomes something you can aim at.
- 03Sign with your fingerTap the page and a box opens. Sign in it — a stylus works too, and pressure is used where the device reports it.
- 04Download and send it backThe signed file saves straight to your phone, ready to attach to a reply.
Common questions
Do I need to install an app?
No. It runs in the browser you already have, on Android and on iPhone. There is nothing to install, nothing to update and no permissions to grant.
Does it work with a stylus?
Yes, and better than with a finger. A stylus always draws rather than moving the page, and where the device reports pressure it is used, so the stroke thickens and thins the way handwriting does.
Can I sign a document that came in as an email attachment?
Yes. Save the attachment to your phone, open it here, sign it, and the signed copy downloads back to the same place ready to attach to your reply.
Is my document uploaded anywhere?
No. Every PDF tool here runs inside your browser. The file is read from disk, worked on in memory, and written back out — it is never sent to a server. That matters more for documents than photos: contracts, statements and ID scans are exactly the things you should not be uploading to a stranger's website.