The fastest way: use Word's built-in signature tool

Open the Word document on your iPhone in the Microsoft Word app, then tap the location where you want the signature to appear. Tap Insert at the bottom of the screen, then Signature. You'll see two options: Draw or Type. If you choose Draw, use your finger to write your signature directly on the screen. If you choose Type, enter your name and Word will format it as a signature. Either way, tap Insert to place it in the document.

This method creates a visual signature — it looks like your handwriting or typed name — but it is not a digital signature that cryptographically verifies who signed the document. If the document needs legal proof that you signed it, this approach alone may not be enough. But for most everyday documents — contracts between people who know each other, internal approvals, or forms where a visual signature is the standard — it works fine.

After you add the signature, save the document by tapping the three dots in the top right corner and selecting Save. The signature stays in place and travels with the file.

Key Takeaways

  • Word's built-in signature tool lets you draw or type a signature directly into the document using your iPhone.
  • A visual signature (drawn or typed) is not the same as a digital signature — it does not cryptographically prove who signed the document.
  • For documents that need legal proof of identity, you may need a digital signature service like DocuSign or Adobe Sign instead.
  • Always save the document after adding a signature so the signature stays in the file.
  • If the document is password-protected or read-only, you may need to request edit access from the person who sent it to you.

When to use a digital signature service instead

If the document is a contract, a legal agreement, or something that will be used as evidence in a dispute, a visual signature in Word may not be enough. Banks, government agencies, and law firms often require a digital signature — one that uses encryption to prove the document has not been changed since you signed it and that you were the one who signed it.

DocuSign and Adobe Sign are the most common services for this. Both let you upload a Word document, add your signature, and create a record that proves when and where you signed. DocuSign is free for up to three documents per month; Adobe Sign's free tier is more limited. If you sign documents regularly, a paid plan may be worth it. Both services send you a copy of the signed document and keep a record you can retrieve later.

To use either service on your iPhone, read the app, create an account, and upload your Word document. The service will ask you to place your signature at specific locations or sign the entire document. Once you confirm, the service sends the signed version back to you as a PDF or Word file.

Signing a document someone else sent you

If someone sent you a Word document and asked you to sign it, the document may be set to read-only mode. Try opening it and tapping where you want to sign. If you see a message saying the document is read-only, tap Edit Document at the top of the screen. Word will ask if you want to enable editing — tap Enable Editing to proceed.

Once editing is on, follow the steps above to add your signature using Word's built-in tool or a digital signature service. If the document came from a business or legal context, ask the sender which method they prefer — some organizations have specific requirements about how signatures must be added.

After you sign, you can send the document back by tapping the three dots, selecting Share, and choosing how to send it (email, Messages, or another app). Make sure you save it first so your signature is included in the file you send.

Using your iPhone camera to add a scanned signature

If you have a physical signature you want to use — for example, a signature you wrote on paper — you can photograph it and insert it as an image. Write your signature on a white piece of paper, take a clear photo with your iPhone camera, and save it to your Photos app. Open the Word document, tap Insert, then Pictures, and select the photo of your signature.

Resize and position the image where you want it in the document. This method works well if you want your actual handwritten signature to appear in the document, but it is still a visual signature, not a digital one. The image can be edited or removed by anyone with access to the document, so it does not provide the same legal protection as a true digital signature.

Troubleshooting common problems

If the signature tool does not appear when you tap Insert, make sure you are using the latest version of the Microsoft Word app. Open the App Store, search for Microsoft Word, and tap Update if one is available. Older versions of Word may not have the signature feature.

If you signed the document but the signature disappeared when you reopened it, the document may not have saved properly. Tap the three dots and select Save when ready after adding the signature. If you are using OneDrive or SharePoint to store the document, make sure you have a stable internet connection — Word may not save changes if the connection drops.

If someone else needs to sign the same document after you, save it and send it to them. They can open it, add their signature in a different location, and send it back. Word does not have a built-in workflow for multiple signers on one document — for that, use DocuSign or Adobe Sign, which are designed to route documents between signers automatically.

Saving and sharing a signed document

After you add your signature, save the document by tapping the three dots and selecting Save. Word will save it in its original format (usually .docx). If you want to send it as a PDF instead — which prevents further editing and is often preferred for signed documents — tap the three dots, select Share, then Send as PDF.

You can also export the document as a PDF by tapping the three dots, selecting Export, and choosing PDF. This creates a copy in PDF format while keeping the original Word file on your phone. PDFs are harder to edit after signing, so they are a safer choice if the document is important.

To send the signed document, tap Share and choose your method: email, Messages, AirDrop, or another app. Make sure the file you are sending includes your signature — open it one more time to confirm the signature is visible before you send it.

Frequently Asked Questions

Is a signature I draw on my iPhone legally binding?

A drawn or typed signature in Word is legally binding in most places, as long as both parties agreed to sign electronically. However, it does not prove you were the one who signed it — anyone with access to the document can add or change the signature. For high-stakes documents, a digital signature from DocuSign or Adobe Sign is safer because it includes a timestamp and proof of identity.

Can I use the same signature for every document?

Yes. Once you create a signature in Word, you can reuse it by copying and pasting it into other documents, or by drawing the same signature each time. If you use a digital signature service, you can save your signature in your account and explore it to multiple documents without redrawing it.

What if I make a mistake and need to change my signature?

If you have not saved the document yet, tap Undo (the curved arrow at the top left) to remove the signature. If you have already saved it, open the document, tap on the signature to select it, and press Delete. Then add a new signature in the same spot and save again.

Do I need the Word app, or can I use Word Online?

The signature tool works best in the Word app on your iPhone. Word Online (the browser version) has limited signature features. read the free Microsoft Word app from the App Store for the full experience.

Can someone forge my signature if I send them a signed Word document?

Yes, if you send a Word document with a visual signature, anyone can open it and copy your signature to use on other documents. If this is a concern, send the document as a PDF instead, which is harder to edit. For documents where forgery is a real risk, use a digital signature service that ties your signature to your identity and the specific document.