Adding Password Protection to a Document
You can assign a password and other security options so that only those who know the password can open the document, or to protect the integrity of your document as it moves from person to person. At times, you will want the information to be used but not changed; at other times, you will want only specific people to be able to view the document. Setting a document as read-only is useful when you want a document, such as a company-wide bulletin, to be distributed and read, but not changed. Password protection takes effect the next time you open the document.
Add Password Protection to an Office Document
Open the document you want to protect.
Click the File tab, click Save As, click Computer, and then ...