Passwords have a number of uses; for example, you can:
When you create a password, write it down and keep it in a secure place. If you lose the password, you cannot open or gain access to the password-protected file.
Passwords are case-sensitive, so if you vary the capitalization when you assign the password, users must type the same capitalization when they enter the password.
A password can contain any combination of letters, numerals, spaces, and symbols, and it can be up to 15 characters long. If you select advanced encryption options, you can make a password even longer.