How to Sign a PDF on iPhone (Without Installing an App)

Someone emails you a PDF to sign and you are away from your computer. On an iPhone you do not need to print, scan or install anything. Here are three ways to do it.

Option 1: Markup in Mail or Files

iOS has a built-in signature tool called Markup.

1. Open the PDF attachment in Mail, or save it to the Files app and open it there.
2. Tap the Markup icon (a pen tip in a circle).
3. Tap the + button and choose Add Signature.
4. Sign with your finger on the screen. Rotate the phone sideways for more room.
5. Tap Done, then drag the signature into place and resize it with the blue handles.
6. Tap Done again. In Mail, you can reply with the signed document attached.

Your signature is saved for next time, so future documents take seconds.

Option 2: the Files app for multiple pages

If you need to sign or initial several pages, open the PDF in Files, use Markup on each page, and add Text boxes for the date and your printed name. The changes are saved into the PDF when you tap Done.

Option 3: a browser PDF editor

If you want typed signatures, stamps, or more control over placement, a browser editor works on iPhone too.

1. Open Docento.app in Safari.
2. Tap to choose the PDF from Files, iCloud Drive, or your Downloads.
3. Select the signature tool and draw, type, or upload your signature.
4. Place it on the page, then add the date with the text tool.
5. Download the signed PDF and share it from the Files app.

The file is processed in the browser rather than uploaded to a server. Saved signatures stay in that browser's local storage on your device.

Tips for a clean signature on a small screen

• Turn the phone sideways before drawing.
• Use a stylus if you have one; even a cheap capacitive stylus helps.
• Sign larger than you need, then shrink it. Shrinking hides wobbles.
• Zoom in on the signature line before placing, so it sits on the line instead of floating above it.
• Check the whole document for every place that needs a signature or initials before sending.

Is a finger signature legally valid?

For most everyday agreements, such as rental applications, consent forms and simple contracts, a drawn electronic signature is legally accepted in the US, the UK, the EU and many other places. Some documents need more, such as wills, certain property deeds, or documents that require a qualified signature or notarisation. See is it legal to sign documents electronically?.

Common problems

• The Markup button is missing: the file may not be a PDF, or it may be password protected. Save it to Files first.
• The signature disappears after sending: some apps flatten annotations differently. Send from Files, or flatten first. See how to flatten a PDF.
• The form fields will not accept typing: see how to fill a PDF form on iPhone.

Takeaway

Markup handles quick signatures on iPhone with nothing to install. For typed signatures, initials on many pages or a bit more control, use a browser editor. For Android, see how to sign a PDF on Android.