You can password-protect a document in Word 2003 so that only authorized users can open or modify its contents. Note that a skilled hacker may be able to break the encryption, but password protection may work in some cases. To enable this feature:
1. Open the document you want to protect.
2. Choose “Tools” then “Options”.
3. When the “Options” multi-tabbed dialog box appears, click the “Security” tab.
4. Next to “Password to open” type in the password necessary to view the document. If you wish, click the “Advanced” button to choose a different encryption type than the default.
5. Next to “Password to modify” type in the password necessary to make changes to the document.
6. Click “OK” to close the dialog box.