How to Sign a PDF on iPhone

Someone sent you a PDF to sign, and you only have your phone. You can sign it right there, with your finger, for free. There are two ways.

1. Apple's Markup, built into the Files app and Mail. Free, and already on your iPhone.
2. PDFlow, the app I built. Also free for signing. It keeps your original file and puts the other PDF jobs in the same place.

Quick answer: Open the PDF in the Files app. Tap the Markup button (the pen tip). Tap +, then Add Signature. Sign with your finger, tap Done, drag the signature into place, and tap Done again.

Table of Contents

• Sign a PDF on iPhone with the Files App (Free)
• Sign a PDF Attachment in Mail (Free)
• Sign a PDF on iPhone with PDFlow
• What Is Free
• Frequently Asked Questions

Sign a PDF on iPhone with the Files App (Free)

This is the way most people need. It costs nothing and needs no app.

1. Save the PDF to the Files app, then tap it to open it.
2. Tap the Markup button. It looks like a pen tip in a circle.
3. Tap +, then Add Signature.
4. Sign in the box with your finger, then tap Done. Your iPhone keeps the signature for next time.
5. Drag the signature to the line. Drag a corner to make it bigger or smaller.
6. Tap Done.

One thing to know: Files saves the signature into that same file. The unsigned copy is gone. If you might need the blank form again, duplicate it first (press and hold the file, then tap Duplicate).

Sign a PDF Attachment in Mail (Free)

If the PDF came by email, you can sign it without saving it anywhere.

1. Open the email and tap the PDF attachment.
2. Tap the Markup button.
3. Tap +, then Add Signature, and sign or pick your saved signature.
4. Drag it into place, then tap Done.
5. Mail offers to reply with the signed PDF attached. Send it.

Sign a PDF on iPhone with PDFlow

If Apple's Markup does the job, use it. Here is when PDFlow helps:

• Your original stays. PDFlow saves the signed file as a new version. The unsigned PDF is still there in the document's history.
• The next job is in the same app. Sign, then compress the PDF to get under an email limit, or delete the pages you don't need to send.
• Nothing is uploaded. Your signature is saved inside the app, on your phone. It is not sent to iCloud or to any server.

Step 1: Import the PDF and open it

Open PDFlow, tap +, and bring in the PDF from Files or Google Drive. Tap the document in your list to open it.

Step 2: Tap Markup & Sign

The document opens on its history. Tap Markup & Sign. If the PDF has form fields, you will also see Fill Form, so you can type your name and date into the fields first.

Step 3: Draw your signature once

Tap the signature button at the top, then Create Signature. Sign inside the box with your finger and tap Save. PDFlow keeps it for next time, so you only do this once.

Step 4: Place it on the page

Tap the signature button again, then Place Signature. It lands low on the right of the page, where most signature lines are. Drag it onto the line. On iOS 26 you can also resize it with its handles. To sign another page, move to it with the arrows at the top and place it again.

Step 5: Tap Done and send it

Tap Done. PDFlow saves a new version called Marked Up. Tap the share button to send it by Mail, save it to Files, or AirDrop it.

Download PDFlow on the App Store →

What Is Free

• Apple's Markup: free, built into iPhone.
• Signing in PDFlow: free, with no limit, and it stays free after the trial. You do not pay to save or share a signed PDF.
• Rotate, reorder and delete pages in PDFlow: free, with no limit.
• Compress: one a day free. Merge: three times free.
• Everything else (split, password protect, remove a password, PDF to images): a three-day free trial, then $19.99 once. Or $2.99 for one month, which does not renew.

Frequently Asked Questions

Can you sign a PDF on your iPhone?

Yes. Open the PDF in the Files app, tap Markup, tap +, and tap Add Signature. You sign with your finger and drag the signature into place. It is free and built into iPhone. PDFlow can sign a PDF too, and keeps your original file.

How do you sign a PDF on iPhone with your finger?

In Apple's Markup or in PDFlow, you draw your signature in a box with your fingertip. Both apps save it, so you draw it once and place it again on every document after that. An Apple Pencil is not needed on iPhone.

How do I fill and sign a PDF on iPhone?

If the PDF has form fields, tap a field and type. In PDFlow, open the document and tap Fill Form, then Markup & Sign. If the PDF has no fields, use Markup to add your signature, and add text with Markup's text tool.

Is a signature drawn on iPhone a legal electronic signature?

It is a picture of your signature, placed on the page. Many people accept that for forms, leases and permission slips. Some ask for a signed-in e-signature service with an audit trail instead. If they sent you a link to one, use their link. If you are not sure, ask the person who sent the PDF.

Is my signature uploaded anywhere?

Not by PDFlow. It saves your signature as an image inside the app on your phone, not in iCloud and not on a server. The signed PDF only leaves your phone when you send it.

Related Guides

• Edit a PDF on iPhone: everything you can do to a PDF on the phone
• Compress a PDF on iPhone: make the signed file small enough to email
• Delete pages from a PDF on iPhone: send only the pages they asked for
• Password protect a PDF on iPhone: lock the signed copy before you share it

PDFlow is on the App Store for iPhone and iPad. It needs iOS 17 or later.