How to sign a PDF on your phone

Option 1: On an iPhone, with Markup

iPhones can sign PDFs without installing anything. Markup is built into the Files app and Mail.

• Save the PDF to the Files app, or open the attachment in Mail.
• Tap the Markup button (the pen icon).
• Tap the plus (+) button and choose Add Signature, then draw your signature with your finger.
• Drag the signature into place, resize it, and tap Done.

Option 2: With a PDF app (iPhone or Android)

Android has no single built-in signing tool across all phones, so most people use a PDF app. Adobe Acrobat Reader, for example, has a Fill & Sign feature: open the PDF in the app, choose Fill & Sign, create your signature, and tap where it goes. This suits people who sign PDFs often and do not mind installing an app.

Option 3: In your browser, with nothing to install

PactPen’s free Sign a PDF tool runs in the phone’s browser, on iPhone and Android alike. The file is opened on your phone and never uploaded.

• Open pactpen.com/tools/sign-pdf and choose the PDF from your phone’s files.
• Type your name in a handwriting style, or draw your signature with your finger.
• Tap the page where the signature goes, drag it into place, and download the signed PDF.

Which one should you use?

• On an iPhone, for a one-off signature: Markup is already there.
• If you sign PDFs every week: a PDF app keeps your signature for next time.
• On a phone where you cannot install apps, or for a quick signature on Android: the browser tool.

When a signature image is not enough

All three methods add a picture of your signature to the page, the electronic equivalent of signing a printout. That is often fine. When the other side needs proof of who signed and when, for example a contract between companies or an employment offer, they should send it through an e-signature service that records each signer’s consent, the time and the IP address, and attaches a certificate of completion.