The fastest way to sign on iPhone is the built-in markup tool in the Files app or Mail

You can sign a PDF or image on your iPhone without downloading anything extra. Open the document in Files, Mail, or Notes, tap the markup button (it looks like a pen tip in a circle), select the signature tool, and draw your name. The signature stays on the document and you can save or send it immediately.

If you sign documents regularly, you can also save your signature as a reusable image so you do not have to draw it each time. This takes about two minutes to set up and works across most apps on your phone.

Key Takeaways

  • The Files app and Mail both have built-in markup tools that let you sign PDFs without installing anything new.
  • You can save your signature once and reuse it on future documents instead of drawing it every time.
  • Signing on iPhone creates a visual signature on the document itself, not a legally binding digital signature that encrypts the file.
  • For documents that require encrypted digital signatures (like tax forms or contracts with legal weight), you will need a third-party app like Adobe Sign or DocuSign.

Signing a document using the built-in markup tool

Open the PDF or image in Files, Mail, Notes, or any app that shows documents. Tap the document to make sure it is active, then look for the markup button — a circle with a pen tip inside. On most iPhones, this button appears in the top right or bottom of the screen.

Tap the markup button, then tap the pen or marker icon at the bottom of the screen. You will see a row of drawing tools. Tap the signature tool (usually the rightmost icon, which looks like a cursive line or initials). Draw your signature on the document with your finger, then tap Done. The signature is now part of the document.

To save the signed document, tap Save or Done again depending on which app you are using. In Mail, the document stays attached to your email. In Files or Notes, the document saves to that app's storage.

Saving your signature to reuse it

If you sign documents often, you can save your signature as a reusable image. Open any document in the markup tool and draw your signature as described above. Before tapping Done, look for an option that says "Save Signature" or "Add Signature" — the exact wording depends on your iOS version.

Tap that option and your signature is now stored on your phone. The next time you need to sign a document, open the markup tool, tap the signature tool, and your saved signature appears as an option. Tap it to place it on the document without drawing again. You can resize it by pinching and dragging the corners.

If you want to delete a saved signature or create a new one, go to Settings > General > Reset and look for "Reset Signature" or "Clear Saved Signatures." You can then save a new one the same way.

Signing documents in Mail

When you receive a PDF attachment in Mail, you can sign it without leaving the email. Open the email, tap and hold the PDF attachment, then select "Quick Look" or tap the attachment preview. Once the PDF opens, tap the markup button and follow the steps above to add your signature.

After signing, tap Save or Done. The signed document stays attached to the email thread. You can then send the email with the signed attachment, or save the document to Files for your records. The recipient sees the signed PDF when they open the attachment.

When you need a legal digital signature instead

The signature you draw on your iPhone is a visual signature — it looks like your handwriting on the document, but it does not encrypt the file or create a legally binding digital record. For documents that require a true digital signature (contracts, tax forms, loan documents, or anything with legal weight), you need a different approach.

Apps like Adobe Sign, DocuSign, and HelloSign create encrypted digital signatures that prove the document has not been changed since you signed it and prove you signed it at a specific time. These apps cost money or require a subscription, but they are the standard for legal and financial documents. If someone asks you to sign a contract or official form, ask them which app or service they use — they usually have a preference and may provide a link.

Troubleshooting common signing problems

If the markup button does not appear, make sure you are viewing the document in an app that supports markup. Files, Mail, Notes, Photos, and Safari all have it. Some third-party apps (like certain banking apps) do not allow markup for security reasons. In that case, you may need to download the document, sign it in Files, and upload it back.

If your saved signature does not appear when you tap the signature tool, your phone may not have stored it correctly. Try drawing and saving it again, making sure you tap the "Save Signature" option before tapping Done. If the problem continues, reset your signatures in Settings and create a new one.

If the signed document looks blurry or the signature is hard to read, you may have drawn too quickly or with too light a touch. Try signing again more slowly and with a bit more pressure on the screen. You can also use a stylus (like an Apple Pencil on iPad) for cleaner lines, though it is not required for iPhone.

Frequently Asked Questions

Can I sign a document on iPhone and send it to someone else?

Yes. After signing in the markup tool, save the document, then open it in Mail or another sharing app and send it as an attachment. The recipient receives the PDF with your signature already on it. They can open it, view your signature, and use it as they need to.

Is a signature I draw on my iPhone legally valid?

A visual signature (what you draw with your finger) is legally valid in most places for most documents, as long as both parties agreed to sign electronically. However, contracts and official documents often require an encrypted digital signature from a service like DocuSign or Adobe Sign, which proves the document has not been altered and creates a timestamped record. Check with the person or organization asking you to sign which type they need.

What if I make a mistake while signing?

Tap the undo button (usually a curved arrow at the top of the markup screen) to remove your last stroke. You can undo multiple times to erase the entire signature and start over. If you already saved the document, you can reopen it and use the markup tool again to sign over the old signature or erase it completely.

Can I sign a document that is not a PDF?

Yes. The markup tool works on PDFs, images (JPG, PNG), and screenshots. If you have a document in another format (like Word or Excel), convert it to PDF first using the share menu, then sign the PDF. Most apps have a "Print to PDF" or "Save as PDF" option in the share menu.

Do I need an Apple ID or internet connection to sign documents?

No. Signing with the built-in markup tool works offline and does not require an Apple ID. If you use a third-party app like DocuSign, you will need to create an account and may need internet to send the signed document, but the signing itself can happen offline on some apps.