Password protecting Microsoft Word and Excel documents
Open Microsoft Word or Microsoft Excel and the document you wish to password protect.
Click Save As
In the Save As window, click the Tools option in the upper right-hand side of the window.
From the Tools drop-down menu, select General Options
This will open a Save window that will allow you to specify a password used to open the file or modify the file.
Password to open - Entering a password for this option will make the file only readable to the users who know the password.
Password to modify - Entering a password for this option will allow users to view the file but only edit and save the file if they know the password. Keep in mind, however, that a user could open the file, copy the contents of the file to another file, and modify and create their own document.