You can electronically sign a Word document in three ways: add a certificate-based digital signature inside Word, save the file as a PDF and sign the PDF, or send it through an e-signature service that collects every signature and keeps a record. The first suits documents you sign and send out yourself. The last suits anything someone else has to sign.

If all you want is a picture of your signature or a drawn one on the page, that’s a different job, and our guide on how to insert a signature in Word covers images, the Draw tab and signature lines step by step. This guide is about the bigger question: getting a Word document signed in a way that holds up, whether the signer is you or a client.

Can you electronically sign a Word document?

Yes, you can electronically sign a Word document, either inside Word with a digital signature or by turning it into a PDF first. Word’s built-in route is the digital signature, which Microsoft describes as an encrypted stamp that “confirms that the information originated from the signer and has not been altered.”

The catch is that Word’s route was built for one person signing with a certificate. It works well for that. It gets awkward the moment you need a customer, a landlord or a new hire to sign, because they’d need a certificate too, and your copy of Word has to trust it.

Which way of e-signing a Word file should you use?

Use a Word digital signature when you’re the only signer, a PDF and a free signing tool when you’re signing something someone sent you, and an e-signature service when other people need to sign. Here’s the short version:

  • Digital signature in Word. Proves the file came from you and hasn’t changed. Needs a digital certificate. Best for reports, policies or letters you send out.
  • Save as PDF, then sign. Quick and free. You place an image of your signature on the page. Best for a form or agreement you need to return today.
  • E-signature service. You upload the document, place fields for each person and send it. Signers sign in a browser, and everyone gets the same finished file with a record of who signed when. Best for anything with a second signer.

Honestly, most small businesses end up using the second and third options far more than the first.

How do you add a digital signature to a Word document?

In the Word desktop app, go to File > Info > Protect Document > Add a Digital Signature, choose a commitment type, type a purpose for signing, and select Sign. That adds an invisible signature: nothing appears on the page, but the file now carries proof of who signed it.

Microsoft lists what happens next. A Signatures button appears in the document, the signature details show up under File > Info, and the file “becomes read-only to prevent modifications.” If you need to change something later, you’d go to File > Info > View Signatures, remove the signature, edit, and sign again.

If you’d rather the signature be visible, add a signature line with Insert > Signature Line and sign it. Signing a line adds a digital signature too. Our Word signature guide walks through the Signature Setup box and what the signer sees.

Do you need a certificate to sign in Word?

Yes, Word’s digital signatures need a certificate. Microsoft says that “to create a digital signature, you need a signing certificate, which proves identity,” and a signature only counts as valid while that certificate is current (not expired). You can get one in three ways:

  1. Buy one from a certificate authority. This is the option Microsoft recommends if you’ll exchange signed documents with other people who need to check your signature. Microsoft notes certificates are usually valid for about a year, after which you renew.
  2. Use one from your employer. Larger companies often issue them to staff.
  3. Make your own with SelfCert. It’s free and instant, but Microsoft warns that “other people cannot verify the authenticity of your digital signature” unless they manually choose to trust your certificate.

A self-made certificate is fine for proving to yourself that a file hasn’t changed. For proving anything to a client, it’s close to useless.

How do you turn a Word document into a PDF for signing?

Open the document in Word, choose File > Save a Copy (or Save As if it’s never been saved), pick a folder, select PDF in the file type list, and select Save. Microsoft gives these steps for the Office desktop apps, and More Options > Options lets you pick a page range or add a password.

Once it’s a PDF, signing it yourself takes a minute. The free Adobe Acrobat Reader has a Fill & Sign tool: open the PDF, choose Tools > Fill & Sign (or click the Sign icon), then type, draw or pick an image of your signature, click where it goes, and save. Adobe says the signature then becomes part of the PDF. On a Mac, Preview does the same job with its Sign button, and you can make your signature with the trackpad, the camera or a nearby iPhone. See how to sign a PDF on a Mac and how to sign a PDF online for the full steps.

Why bother converting? A PDF looks the same on every screen. A Word file can reflow when it’s opened in another version or on a phone, so the page someone signs may not match the page you keep.

How do you get someone else to sign a Word document electronically?

The cleanest way to get someone else’s signature on a Word document is to send it through an e-signature service, which turns the file into a PDF, sends each signer a link, and returns one completed copy to everyone. Some services take the Word file and convert it for you; with others, save it as a PDF first.

Picture a hypothetical: Dana runs a small bookkeeping practice and needs two business partners to sign an engagement letter she wrote in Word. If she emails the .docx, each partner might add a signature image, save their own version, and send it back. Dana now has two files that differ, no record of when either partner signed, and no way to show neither of them edited the fee paragraph first.

With an e-signature service, Dana uploads the letter, drops a signature field and a date field for each partner, and sends it. Both partners sign the same document. When they’re done, the service seals the file and attaches an audit trail showing when it was sent, opened and signed. If more than two people need to sign, or the order matters, how to get a document signed by multiple people covers signing order, copies and reminders.

What makes an electronic signature legally count in the US is mostly intent: the person meant to sign, agreed to do business electronically, and the record can be kept and reproduced later. The method (a digital certificate, a typed name, a drawn squiggle) matters less than people expect.

We’ve covered the law separately rather than squeeze it in here. Are electronic signatures legally binding explains the general rule, and the ESIGN Act explained goes through the federal law itself. A few documents are excluded from these rules altogether, such as wills, so check documents you can’t sign electronically before you send anything unusual.

Where the method does matter is proof. If a dispute ever comes up, a signature image pasted into a Word file shows very little. A digital signature or a sealed PDF with an audit trail shows a lot more.

This article is general information, not legal advice. For a specific contract or dispute, talk to a lawyer licensed where you are.

Is signing a Word document different on a Mac?

Signing a Word file on a Mac works the same way for the PDF and e-signature routes, but Microsoft’s instructions for certificates are written for Windows. Its SelfCert steps, for example, point to SelfCert.exe in the Office installation folder, which is a Windows program, and Microsoft’s pages on digital signatures and signature lines don’t give separate Mac steps.

So if you’re on Word for Mac and can’t find the digital signature options, don’t burn an afternoon on it. Save a copy as a PDF and sign it in Preview, or send it through a service. Both work the same on a Mac as anywhere else.

So which one would I pick?

For a policy memo you’re sending to your own staff, Word’s digital signature is a nice touch, assuming you have a certificate people trust. For a form a vendor emailed you, convert it to PDF and sign it in Acrobat Reader or Preview, then send it back. For a contract, a quote or an offer letter that someone else has to sign, use an e-signature service, because the record it keeps is the part you’ll want if anyone later remembers the terms differently. SignWren does that: send the Word file, check the PDF it becomes, and everyone gets back the same sealed copy with an audit trail. You can start free.