Digital signatures let you identify any unauthorized changes made to a document after it is signed. Documents may be signed several times and by different persons. Certifying a PDF document ensures, in addition to applying a digital signature, that the range of permitted actions is limited.
To sign an open PDF document
Use the Sign tool at Security > Sign and Certify > Sign. Click the arrow for a drop-down list and choose Sign Document.
Click with the pen cursor and click in the page, then click Continue to create an invisible signature. Click Start Over for a visible signature.
Click with the pen cursor and draw a rectangle on the page big enough to contain a signature.
In the Sign Document dialog box, select a Digital ID from the list or click Add to browse for an existing Digital ID or create a self-signed digital ID. Confirm the password if the signature scheme includes password protection, then:
Click Save or Save As for an invisible signature to take effect, or
Click Next, configure the appearance, and click Save or Save As for a visible signature to take effect
To sign and certify an open PDF document
Click the down arrow next to the Certify tool in the same group, and choose Certify Document or Certify Document Invisibly from the drop-down list.
Draw a rectangle to certify the document with a visible signature.
In the Certify Document dialog box, select a Digital ID from the list or click Add to browse for an existing Digital ID or create a self-signed digital ID. Confirm the password if the signature scheme includes password protection. Specify allowed actions by choosing from Allow no changes, Allow form filling only, Allow comments and form filling, then:
Click Save or Save As for an invisible signature to take effect, or
Click Next, configure the appearance and click Save or Save As for a visible signature to take effect.
To use the Sign/Certify Panel for signing and certifying
These actions can be performed more conveniently with the Sign/Certify Panel. This is called from the Panel bar by the following tool:
If you do not see this tool, right-click in an empty area of the Panel bar and select it.
To use an available signature scheme, select its thumbnail in the panel and do one of the following
Drag it to the place on the page where you want to locate it with original sizing.
Double-click with the Sign or Certify Document cursor on the page where you want it located with original sizing.
Draw a rectangle with the Sign or Certify Document cursor to contain the signature, resized to fit into the rectangle.
Note
The Sign/Certify panel displays both visible and invisible signature schemes.