Guide

How to sign a PDF on your phone (Android, free)

An on-device PDF app drops your signature straight onto the page and lets you fill in the rest of the form, all offline, in a couple of minutes — no printing, no rescanning, no website upload.

Key takeaways

App: Any Android PDF app with a Sign or Fill & Sign tool that works on-device — we use PDFPivot (our app).
Internet: Signing runs fully offline, on the device.
Cost: Free for basic signing; some apps show ads or offer an optional paid tier.
Time: Under a minute for one signature; a few minutes for a full form.

What's the fastest way to sign a PDF on Android?

Open the PDF in an app with a Sign or Fill & Sign tool, draw your signature with your finger (or reuse a saved one), place it on the line, fill any other form fields, and save. No printer, no scanner, no upload.

How do you sign a PDF on Android, step by step?

Install a PDF app that signs on-device. We build one called PDFPivot (our app) with a Sign and Fill & Sign tool that works locally. Any app that signs offline works the same way.
Open the document and tap Sign, or Fill & Sign if it has form fields.
Draw your signature with your finger, or place a signature you saved earlier, then drag it onto the signature line and resize it if needed.
Fill in any remaining fields — name, date, checkboxes — then save. The signed PDF is written to your device.

Why sign on-device instead of a signing website?

Privacy. Signing websites upload your document, which may contain personal or financial details, to their servers.
No account needed. On-device apps let you sign a form straight away, with no sign-up and no email verification.
Works anywhere. No connection required, useful when a form is due and you're offline.

What can go wrong when signing a PDF on Android?

There's no visible line to place your signature on. Plenty of PDFs arrive without a defined signature field. Drag your signature image to wherever it needs to sit on the page.
Tapping a form field does nothing. Some PDFs are "flat" — scanned or exported as plain pages — so there is nothing for the app to detect. Use a Fill tool that places free text boxes anywhere on the page.
A saved signature looks jagged when resized. A signature drawn small and then stretched large can look rough. Draw it at roughly the size you'll actually use, or use an app that saves it as a vector rather than a low-resolution image.

If the document needs other changes too, you can edit its text or images first, merge it with other pages, or compress it before sending the signed copy on.

Frequently asked questions

Is a signature added on your phone legally valid?

A drawn or placed signature image counts as an electronic signature in most everyday contexts — leases, forms, informal contracts. In the US, the ESIGN Act gives electronic signatures the same legal weight as a handwritten one for interstate and foreign commerce. For documents that need a certified digital signature or notarization, check the recipient's specific requirements first.

Is signing a PDF on Android free?

Yes, many Android PDF apps include signing and form-filling for free, sometimes with ads or an optional paid tier.

Does signing a PDF on my phone upload it to a server?

Only if you use a browser-based signing site. An on-device app adds the signature locally, so the file stays on your phone.