Info: Password Protect a File Adding a Password to a file increases the security. This is called encryption.   Passwords should not be easy to guess, such as your name or birthday. You should choose a password that is at least 6 characters long and includes letters and numbers.   4. Try it: Encrypt the Document Go to File ->Info_>Protect Workbook. Click on Encrypt with Password.   What Do You See? You will be prompted to enter a password. Anyone who opens your file will be asked for a password as well.   Click CANCEL. Keep going...   Memo to Self: Microsoft takes security seriously and strives to meet Department of Defense standards. There is NO UNDO if you forget the password! File ->Info->Protect Workbook->Encrypt with Password