Any changes to a document signed with sign | pro PDF will be detected, resulting in the signature being invalidated. To ensure that changes can’t be made, you can encrypt the document with a password, apply a password to restrict editing and printing, or require a password in order to open the document. To encrypt your document and select permission options:
- Go to "Change Permissions" in the "Sign Document" dialog box that appears when you add a signature.
- Click "Add Signature" on the toolbar button.