The simplest way to sign on iPhone is through the built-in tools in Mail, Messages, and the Files app — no separate software needed

Your iPhone comes with signature tools already installed. The most common route is opening a PDF in Mail or the Files app, tapping to add your signature, and signing with your finger on the screen. For documents people send you, you can often sign and send back in the same conversation. For your own documents, you can save a signature once and reuse it across multiple files.

The method you use depends on how the document reached you. If someone emailed it, signing in Mail is fastest. If it's stored in iCloud Drive or another cloud service, the Files app works. If you need to sign something on your own device without sending it anywhere first, you can create and save a signature in the Notes app or use the Markup tool in Photos.

Key Takeaways

  • Mail, Messages, and the Files app all have built-in signature tools — you do not need to download anything extra.
  • You can create a signature once in Mail and reuse it on future documents, or draw a new one each time.
  • Signing a PDF in Mail or Files takes about 30 seconds: open the document, tap the markup icon, draw your signature, and save.
  • If you need to sign something stored in Google Drive, Dropbox, or OneDrive, open it in the Files app first, then use the built-in markup tools.

Signing a document someone emailed you

When someone sends you a PDF or image in Mail, you can sign it without leaving the email. Open the message, tap and hold the attachment, then tap "Quick Look" or just tap the document to open it. Look for the markup icon — it looks like a pen tip in a circle, usually in the bottom right corner or top toolbar. Tap it.

A menu appears with options including a signature tool (often labeled with a pen or signature icon). Tap the signature option. If this is your first time, you will be asked to draw your signature on the screen with your finger. Sign naturally in the box provided. Once you finish, tap "Done" or the checkmark. Your signature appears on the document. Tap "Save" or "Done" again to close markup mode, then reply to the email with the signed document attached or ask Mail if you want to send it back.

If you sign documents regularly, you can save your signature the first time you create it. After you draw it and tap "Done", Mail will ask if you want to save this signature. Tap "Save" or "Yes". The next time you need to sign something, you can tap the signature tool and select your saved signature instead of drawing a new one — it appears instantly on the page.

Signing documents in the Files app

If a document is stored in iCloud Drive, Google Drive, Dropbox, OneDrive, or another cloud service, open it in the Files app. Tap the document to open it, then look for the markup icon (pen in a circle). Tap it, then select the signature tool from the menu that appears.

Draw your signature or select a saved one if you have created one before. Tap "Done" when finished. The signature appears on the page. Tap "Save" to save the changes to the file. The document is now updated in your cloud storage with your signature included.

This method works for PDFs, images, and some other file types. If the Files app does not open your document (for example, if it is a Word file or a format the app does not recognize), you may need to open it in a different app first — the app that created it, or a universal viewer like Adobe Reader.

Creating and storing a signature for reuse

If you sign many documents, creating a saved signature saves time. The easiest way is to sign a document once in Mail or Files, then choose to save the signature when prompted. After that, every time you open the signature tool, your saved signature appears as an option alongside the option to draw a new one.

You can also create a signature in advance without a document open. Open the Settings app, scroll down to "Mail", tap it, then scroll to "Signatures". Tap "All Accounts" or a specific email account. Tap "Add Signature" and draw your name or initials in the box. Tap "Save". This signature is now stored and will appear as an option whenever you use the signature tool in Mail.

You can create multiple signatures if you want — for example, a formal full signature for contracts and a quick initial for casual documents. Each one is stored separately and you choose which one to use each time you sign.

Using Markup to sign documents in Photos or Notes

If you have a photo of a document or a screenshot, you can sign it using the Markup tool in the Photos app. Open the photo, tap "Edit" in the top right, then tap the three circles icon (Markup). Tap the pen or marker icon at the bottom, then look for the signature tool in the menu. Draw your signature on the image and tap "Done". Tap "Save" to save the marked-up photo.

In Notes, you can also add a signature. Create a new note or open an existing one, tap the drawing icon (looks like a pen tip), then select the signature tool from the menu. Draw your signature and tap "Done". The signature is now part of your note. You can share the note or take a screenshot of it to send as a document.

These methods are useful when you need to sign something quickly or when the document is not a formal PDF — for example, signing a photo of a receipt or adding your name to a screenshot.

What happens after you sign

Once you sign a document in Mail, you can reply to the email with the signed version attached, or Mail may automatically include it in your response. In the Files app, the signed document is saved to the cloud storage where it was stored — the person who sent it can download the updated version from there.

If you are signing something that will be legally binding — a contract, a form for a bank, a government document — check with the other party first about whether a digital signature created this way is acceptable to them. Most organizations accept signatures made on an iPhone, but some require a specific type of digital signature or a wet signature (one made with pen and paper). Asking first prevents you from signing something that will not be recognized.

Keep a copy of any signed document for your records. Take a screenshot or save the file to your own storage so you have proof of what you signed and when.

Frequently Asked Questions

Can I sign a document that is not a PDF?

Yes, if the Files app or Mail can open it. Images, screenshots, and some other formats work. Word documents and Excel files usually need to be opened in their original apps first (Microsoft Word, Google Docs, etc.) before you can add a signature. If the app does not have a built-in markup tool, you may need to convert the file to a PDF or image first.

What if I make a mistake while signing?

Tap "Undo" (the curved arrow icon) before you tap "Done" to remove the signature and try again. If you have already saved the document, you can open it again, tap the markup icon, and draw over the old signature with a new one, then save again.

Is a signature made on my iPhone legally valid?

In most cases, yes — digital signatures are legally recognized in the United States and many other countries. However, some organizations (banks, government agencies, legal firms) may require a specific type of digital signature or a traditional pen-and-paper signature. Always check with the person or organization requesting the signature before you sign.

Can I sign a document and send it back without leaving Mail?

Yes. Open the document in Mail, sign it using the markup tool, tap "Done", then tap "Reply" or "Forward". The signed document is attached to your message. Type your response and tap "Send".

Do I need to download an app to sign documents on my iPhone?

No. Mail, Messages, and the Files app all have signature tools built in. You do not need to download anything extra unless you want advanced features like adding initials, timestamps, or specific signature formats that third-party apps provide.