To Sign an Entire File

From the Digital Signatures dialog, select the Add File Signature icon.
The Add File Signature dialog opens. The name of the signer is filled in from the selection of the certificate. The location defaults to the computer name.
Select a certificate from your personal certificate store.
(Optional) Enter the reason the file is being signed in the Purpose field.
(Optional) Enter the date the signature expires in the Expiry field.
(Optional) Click the Dependent Signature check box if you want to create a signature hierarchy.
(Optional) Click the Include References check box if you want the contents of all references attached to the master file to be included in the signature.
Click OK.
The new signature is annotated automatically with the current time from the signer’s machine.