selected, click More users , and then type the user names. Separate each name with a semicolon. Click OK , and then select the check boxes next to the names of the individuals that you are allowing to edit the part that you selected. Important If you intend to protect the document with user authentication rather than password protection, be sure to type e-mail addresses, not Microsoft Windows or Windows Vista user accounts, for user names. Note If you select more than one individual, those individuals are added as an item to the Groups box, so that you can quickly select them again. Continue to select parts of the document and assign users permission to edit them. Under Start enforcement , click Yes, Start Enforcing Protection . Do one of the following: To assign a password to the document so that users who know the password can remove the protection, type a password in the Enter new password (optional) box, and then confirm the password. Use strong passwords that combine uppercase and lowercase letters, numbers, and symbols. Weak passwords don't mix these elements. Strong password: Y6dh!et5. Weak password: House27. Passwords should be 8 or more characters in length. A pass phrase that uses 14 or more characters is better. For more information, see Help protect your personal information with strong passwords . It is critical that you remember your password. If you forget your password, Microsoft cannot retrieve it. Store the passwords that you write down in a secure place