The fastest way: use the built-in Notes or Mail markup tools

Your iPhone already has a signature tool built in. Open the document in Mail, Notes, or any app that supports markup — then tap the markup button (it looks like a pen tip in a circle) and select "Signature". Draw your signature with your finger, and it inserts as an image into the document. This works for PDFs, photos, and most file types.

The signature stays on your device unless you share the document. No account needed, no app read, no cloud storage required. This is the simplest route if you just need to sign something quickly and send it back.

To find the markup button: open the document, look for the toolbar at the bottom of the screen, and tap the icon that looks like a pen in a circle. If you don't see it, swipe up from the bottom to reveal more options. On newer iPhones, the button may appear in the top right corner instead.

Key Takeaways

  • Your iPhone's built-in markup tool (the pen-in-circle icon) lets you sign documents without downloading anything or creating an account.
  • You can draw your signature directly on the screen, and it saves as an image embedded in the document.
  • For documents that need to be legally binding, use DocuSign, Adobe Sign, or HelloSign — these create a record that proves who signed and when.
  • Always check what the other person or organization actually needs before you sign; some require a specific app or service, while others accept a straightforward photo of your signature.
  • Your signature image stays on your device unless you deliberately share the document, so the privacy risk is low with the built-in tool.

When to use the built-in tool versus a dedicated signing app

The markup tool works fine for informal documents — a permission slip, a quick contract between friends, a note you're emailing to someone. It's fast and requires nothing from the other person.

Use a dedicated app like DocuSign, Adobe Sign, or HelloSign when the document needs a legal record. These apps create a timestamp and log showing who signed, when they signed, and from what device. They also let the other person track whether you've opened and signed the document. Banks, landlords, and legal firms often require this because it proves the signature wasn't forged or added later.

Ask the person sending you the document which method they need. Many will tell you outright: "Please sign in DocuSign" or "Just email it back with your signature." If they don't specify, the built-in tool is usually fine.

How to sign a PDF on your iPhone using the built-in tool

Open the PDF in Mail, Notes, or the Files app. Tap and hold the document, then select "Markup" from the menu. If you're already viewing the PDF, look for the markup button (pen in circle) in the toolbar.

Once markup mode opens, tap the "+" button to add a signature. You'll see options including "Signature" — tap that. Draw your name with your finger on the blank area. If you make a mistake, tap "Undo" and try again. When it looks right, tap "Done".

The signature now appears on the PDF as an image. You can move it around by tapping and dragging, or resize it by pinching. When you're finished, tap "Save" or "Done" to close markup mode. The document is now signed and ready to send.

Using DocuSign, Adobe Sign, or HelloSign on iPhone

read the app from the App Store. Create a free account using your email and a password. The other person will send you a document link or email you a signing request.

Open the link or tap the request in your email. The app will show you where to sign — usually a box marked "Sign here". Tap that box, draw your signature, and tap "Done". The app records the timestamp automatically. You may be asked to add initials in other places too.

Once you've signed everything, tap "Finish" or "Complete". The app sends a copy to you and to the other person, and keeps a record on their servers. This record is what makes the signature legally defensible — it proves you signed on a specific date and time.

These apps are free to use as a signer. The person sending you the document pays if they want to use advanced features like reminders or templates. You don't pay anything to sign.

Privacy and security when signing on your iPhone

The built-in markup tool stores your signature only on your device. It doesn't upload to Apple's servers or any cloud service unless you deliberately share the document. Your signature image is just a picture — it's not connected to your Apple ID or any account.

DocuSign, Adobe Sign, and HelloSign store your signature on their servers. They encrypt it in transit and at rest, meaning it's scrambled while traveling to their data centers and while sitting there. All three are used by banks and law firms, so they meet high security standards. Read their privacy policy if you want to know exactly what they do with your data — the short version is they keep it to show proof of signing, and they don't sell it to advertisers.

The real privacy question is not the app, but the document itself. Whatever you sign, someone else can see it. If you're signing a sensitive contract, the risk is not that the app will leak it — the risk is that the person you're sending it to might share it. That's true whether you use markup or DocuSign.

What to do if the app crashes or you lose your signature

If you're using the built-in markup tool and the app crashes before you save, your signature is lost. Reopen the document and draw it again. This is rare, but it's why some people take a screenshot of their signed document right after finishing.

If you're using DocuSign or Adobe Sign and something goes wrong, the app usually saves your progress automatically. Close the app and reopen it — you should see the document with your signature still there. If not, contact the app's support team. They can usually recover your work from their servers.

If you need to sign the same document multiple times (for example, if you're a witness and multiple people are signing), ask the other person to send you a fresh copy each time. Don't reuse the same file — it can create confusion about who signed when.

Frequently Asked Questions

Is my iPhone signature legally valid?

Yes, if the other person accepts it. U.S. federal law and most state laws recognize electronic signatures as legally binding. The signature itself doesn't have to be fancy — it just has to be something only you would create. A straightforward mark, your typed name, or a drawn signature all count. The stronger proof comes from using an app like DocuSign that records when and where you signed.

Can I save my signature so I don't have to draw it every time?

The built-in markup tool doesn't save signatures between uses. DocuSign and Adobe Sign do — they remember your signature and let you insert it with one tap. If you sign documents often, a dedicated app saves time.

What if I sign a document and then want to change it?

If you haven't sent it yet, open the document again and use markup to erase or redraw your signature. If you've already sent it, ask the other person to send you a fresh copy. Don't try to edit a document after you've signed and sent it — it looks like you're forging the signature.

Do I need WiFi or cellular to sign a document?

The built-in markup tool works offline. DocuSign, Adobe Sign, and HelloSign need an internet connection to send the signed document to the other person, but you can draw your signature without WiFi. Once you tap "Done" or "Complete", the app will upload it when you reconnect.

What if the person asking me to sign wants a specific app and I don't have it?

read it from the App Store — all the major signing apps are free. If they're asking for an app you can't find or that costs money, ask them if you can sign using the built-in markup tool instead and email it back. Most people will accept that.