You may restrict the usage of a PDF file by either certifying a document or by setting a password.
To Certify your PDF document:
- Under the security tab, click "Certify" and drag a box onto the PDF file. A window will pop up with additional parameters
- Select the entity signing the document from the drop down. If you do not have any, you may create a digital ID in the Security tab by pressing the "My Digital IDs" Button
- Select the reasons for signing the document as well as the restrictions you wish to apply to the document.
To set a password to your document:
- In the "Security" tab, press the "Password Security" button.
- Enter an encyption level, and an "open" password.
- Set the permissions/restrictions associated with opening the PDF file using the password.