Scenario:
Make: Microsoft
Application: Microsoft Word for Windows [Word 2013, 2016, 2019, 2021, 2024 and Microsoft 365]
Mode: GUI [Graphical User Interface]
Description: In this article, we will discuss a stepwise method of how to digitally sign a Microsoft Word document using a signature line and a digital certificate, how to verify the signature, and what to do if you do not have a certificate yet.
Digital Signature vs. Electronic Signature
Many people think that pasting an image of their handwritten signature into a document is a digital signature. It is not. A real digital signature uses a certificate to prove two things:
- Who signed the document – the signer’s identity comes from a certificate issued by a trusted Certificate Authority (CA).
- That nothing has changed since signing – if anyone edits the document afterwards, the signature automatically becomes invalid.
| Signature Type | How It Works | Security |
| Image of a handwritten signature | A picture pasted into the document | None; anyone can copy or change it |
| Visible digital signature (this guide) | A signature line signed with your certificate | High; tamper-proof and verifiable |
| Invisible digital signature | A certificate signature with no visible line in the document | High; tamper-proof and verifiable |
If you do not need a visible signature line, see Add an Invisible Digital Signature To a Microsoft Word Document.
Prerequisites
- Microsoft Word for Windows (desktop version). Word for the web and Word for Mac do not support adding digital signatures.
- A digital signing certificate installed on your computer, or on a USB token or smart card. These are usually issued by a Certificate Authority, your organisation’s IT team, or, in some countries, as a government-recognised Digital Signature Certificate (DSC).
- The document saved as .docx. Digital signatures are not supported in the older .doc format.
Don’t have a certificate yet? See the section “No Certificate? Create a Test Certificate” below.
Add a Digital Signature Using a Signature Line
Step 1: Choose Where the Signature Goes
Finish editing the document first, because any change after signing invalidates the signature. Then click the place where you want the signature line to appear, usually at the end of the document.
Step 2: Insert a Signature Line
On the Word ribbon, click “Insert” and then “Signature Line” in the Text group. In some versions, click the small arrow next to it and choose “Microsoft Office Signature Line”.
Step 3: Fill In the Signature Setup
In the Signature Setup window, enter the details you want to show under the line, then click “OK”. All fields are optional:
- Suggested signer – the signer’s full name.
- Suggested signer’s title – for example “Network Manager”.
- Suggested signer’s e-mail address.
- Instructions to the signer – a short note shown when signing.
- Allow the signer to add comments and Show sign date in signature line – tick these if needed. Showing the date is recommended.
Step 4: Open the Signature Line
The signature line now appears in the document with an X. Double-click it to start signing.
Step 5: Sign the Document
In the Sign window, type your name next to the X. If you prefer, click “Select Image” to show a scanned image of your handwritten signature instead. Check that the correct certificate is shown under “Signing as”; click “Change” if you have more than one.
Step 6: Add a Signature Image (Optional)
If you chose “Select Image”, browse to the image file of your signature and select it. A PNG with a transparent or white background looks best. The image is only for appearance; the security comes from your certificate.
Step 7: Enter Your Certificate PIN
Click “Sign”. If your certificate is protected, for example on a USB token or smart card, Windows asks for its PIN. Enter it and click “OK”.
Step 8: Confirm the Signature
Word shows a confirmation that the signature was saved with the document.
Your Word document is now digitally signed. Word marks it as final, shows a “Signatures” bar at the top and a red signature badge in the status bar.
Important Note: If anyone edits the document after it has been signed, the signature becomes invalid and must be added again. Always sign the final version.
How to Verify a Digital Signature
Anyone who receives the document can check the signature:
- Open the document and click “View Signatures” in the yellow bar, or go to “File” > “Info” > “View Signatures”.
- In the Signatures pane, a valid signature shows the signer’s name. Click the arrow next to it and choose “Signature Details” to see the certificate and signing time.
- If the pane shows “Invalid signature” or “Recoverable error”, the document was changed after signing, or the certificate is not trusted on that computer.
How to Remove a Digital Signature
Open the Signatures pane, click the arrow next to the signature and select “Remove Signature”. You can then edit the document and sign it again.
No Certificate? Create a Test Certificate
For testing or internal use, you can create a self-signed certificate with Microsoft’s SelfCert tool, included with Office:
- Open the Office installation folder (usually C:\Program Files\Microsoft Office\root\Office16) and run SELFCERT.EXE.
- Enter your name and click “OK”. The certificate is added to your Windows certificate store.
- Return to Word and sign as described above; the new certificate appears under “Signing as”.
A self-signed certificate is only trusted on your own computer. Other people will see a warning, so for official or legal documents, use a certificate from a recognised Certificate Authority.
Troubleshooting
- “Signature Line” is greyed out – the document is probably in .doc format, opened in Protected View, or opened in Word for the web. Save it as .docx in Word for Windows and try again.
- No certificate is shown when signing – make sure the certificate is installed in your personal certificate store and, for USB tokens, that the token is plugged in and its driver is installed.
- The signature shows as invalid – the document was modified after signing, or the recipient’s computer does not trust the issuing Certificate Authority.
- Wrong PIN error – USB tokens lock after several wrong attempts. Contact the certificate provider if your token is locked.
Frequently Asked Questions
Is a Word digital signature legally valid?
In many countries, digital signatures created with a certificate from a recognised Certificate Authority are legally accepted. Rules differ by country and document type, so check local regulations for important legal documents.
Can I digitally sign a Word document on a Mac?
Word for Mac can open and show signed documents, but adding a digital signature requires Word for Windows.
Can I sign a document without a certificate?
You can insert an image of your handwritten signature, but that is not a digital signature and offers no protection against changes. A certificate is required for a true digital signature.
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Source: Knowledge Base, Lab, Microsoft Support
Disclaimer: This article is for educational purposes only and is not professional financial, medical, or legal advice. It may contain affiliate links, which earn us a small commission at no extra cost to you. See our Disclaimer and Affiliate Disclosure.
Article ID: EA00102