Document.WritePassword Property (Word)
Sets a password for saving changes to the specified document. Write-only String .
expression A variable that represents a 'Document' object.
Important Avoid using hard-coded passwords in your applications. If a password is required in a procedure, request the password from the user, store it in a variable, and then use the variable in your code. For recommended best practices on how to do this, see Security Notes for Microsoft Office Solution Developers.
If the active document isn't already protected against saving changes, this example sets "secret" as the write password for the document.
Set myDoc = ActiveDocument If myDoc.WriteReserved = False Then myDoc.WritePassword = "secret"