How to sign a PDF on your phone
- Save the PDF to your phone: in Mail or WhatsApp, open the attachment and choose “Save to Files” (iPhone) or “Download” (Android).
- Open this page and tap “Select PDF file”, then pick the PDF from Files / Downloads.
- Tap “Create signature” and draw with your finger (turn the phone sideways for more room), or type your name.
- Drag the signature into place, resize it with the blue dot and use ‹ › for other pages.
- Tap “Sign & download”, then share the signed PDF from Files or Downloads back to Mail or WhatsApp.
iPhone and iPad tips
Use Safari or Chrome. After downloading, the signed PDF is in the Files app → Downloads. iOS also has a built-in Markup signature, but it is hard to place precisely on small forms and needs several taps per page; bopdf lets you place and resize signatures on any page and add initials or the date with the Type tab.
Android tips
Use Chrome. The signed PDF is saved in Downloads. If tapping “Select PDF file” shows only photos, choose “Browse” or “Files” in the picker to reach your documents.
Is a phone signature valid?
A signature drawn on bopdf is a simple electronic signature — accepted for many everyday documents such as rental forms, consent forms and quotes in most countries. Documents that legally require a certificate-based signature (for example some tax or government filings) need your government’s official signing app instead. Your PDF is processed on the phone itself and never uploaded.
🔒 Your files never leave your device
bopdf processes your documents locally with JavaScript (pdf-lib and Mozilla pdf.js) inside your browser tab. Your PDF is never uploaded, stored or seen by us — you can even disconnect from the internet after the page loads and the tool keeps working. When you close the tab, everything is gone.
Frequently asked questions
Do I need to install an app?
No. bopdf runs in Safari or Chrome. You can add it to your home screen for quick access.
Where is the signed PDF saved?
iPhone: Files app → Downloads. Android: the Downloads folder or the notification after downloading.
Can I sign on an iPad with Apple Pencil?
Yes — the Draw tab works with Apple Pencil and gives a very natural signature.
Can I sign a PDF received on WhatsApp?
Yes. Save the document from WhatsApp to Files/Downloads, sign it here, then attach the signed PDF in WhatsApp.
Are my files uploaded to a server?
No. Everything happens in your browser on your own device. Files are never sent over the internet, which makes bopdf suitable for confidential documents.
Is there a file size limit?
There is no fixed limit, but very large files (hundreds of MB) depend on your device memory. On phones, files up to about 100 MB usually work well.