Sign a PDF in Adobe Acrobat Reader

This how-to will show you how to sign a PDF document in Adobe Acrobat Reader with a document signing certificate from

These instructions were tested with a document signing certificate installed in slot 1a of a YubiKey FIPS, in Acrobat Reader 2019.021.20056, on Windows 10 Home.

1. ships document signing certificates on YubiKey FIPS USB tokens. Make sure the YubiKey is inserted in your computer.


2. Open the document that you want to sign in Acrobat Reader.

Open PDF file


3. Select the Tools tab.

Tools tab


4. Click Certificates.



5. Click Digitally Sign.

Digitally Sign


6. Click the OK button to dismiss the dialog box that appears. You can check Do not show this message again to prevent it from appearing in the future.

Dialog box


7. Use your mouse to draw a box where you’d like the signature to appear.

Draw box for signature


8. A dialog box will appear. Select the certificate you wish to use for signing, then click the Continue button.

Select certificate

If Acrobat Reader shows multiple available certificates and you are not sure which one to pick, you can click the link to View Details for a certificate, then click the Details tab in the Certificate Viewer window to check the serial number. You can then check the certificate’s serial number against the document signing certificate order in your user account.


9. Click the Sign button. You may also optionally choose to lock the document after signing at this point.



10. In the dialog box that opens, enter a filename for the signed PDF, then click the Save button.

Enter filename


11. Enter the PIN for your hardware token, then click the OK button.

Enter PIN


12. You’re all finished! The document has been digitally signed.

Signed document

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