How to Sign a PDF from Gmail on iPhone

Step by step

01
Open the attachment
Tap the PDF in Gmail so the attachment opens in its preview.
PDF SIGN & SCAN / 01
02
Send it to PDF Sign
Tap Share or Open in and choose PDF Sign. If it is not listed, choose More or save the attachment to Files first.
PDF SIGN & SCAN / 02
03
Place your signature
Choose a saved signature, drag it to the signature line, and pinch to set the size.
PDF SIGN & SCAN / 03
04
Return the signed copy
Tap Send, choose Gmail in the iOS share sheet, and attach the exported PDF to your reply.
PDF SIGN & SCAN / 04

Open the exported PDF once and check the page, signature size, and orientation.
Keep the original attachment until the recipient accepts the signed copy.
If the sender requires a certificate or signing portal, use that requested process instead.

What if PDF Sign does not appear in Gmail?

Use More in the iOS share sheet, or save the attachment to Files and import it from inside PDF Sign & Scan.

Does signing change the email attachment?

No. PDF Sign & Scan exports a separate signed copy that you attach to a new message or reply.