with Adobe Acrobat and Adobe Reader
By signing a document, authorship can be proven and unnoticed subsequent changes to the content can be prevented.
Before you can sign PDF documents, you must have requested a user certificate and imported it into the certificate store (Windows) or stored it in the key ring management (Mac).
Open the file to be signed with Adobe Acrobat.
Click on Tools at the top, then go to Certificates and click Open:
Click Sign digitally in the bar at the top:
An explanation follows. Read it and confirm it by clicking OK:
Draw a frame at the point in the document where you want the signature to appear:
Now select your certificate to sign (digital ID) and click Next:
The digital signature is displayed.
If you want to change the appearance (display your own signature or other values) follow these instructions: Link
If the appearance suits you, click Sign:
Save the PDF document.
The PDF document is now signed.
