1. Open the Microsoft Word file.
2. Click Tools menu > Options > "Security" tab.
3. In the "Password to open" box, type a password, and then click OK.
In the "Reenter password to open" box, type the password again, and then click OK.
***Important: Make sure you memorise the password. Otherwise, you will NOT be able to open the document again.
4. You can now test the password by closing the document, and then opening it again. It will prompt you for the password before you open it.