If you forget your login password
If you can’t remember your login password, try the following:
If you forget your password while logging in, click the question mark in the password field to see a hint. If you don’t see a question mark, your user password doesn’t have a hint. For more information, see Add a password hint.
If you must enter an administrator’s name and password but don’t know them, ask the person who set up your Mac for help. If you set up the Mac, the user you created during setup is an administrator.
If you don’t have a password hint, or if you can’t remember your password after displaying the hint in the login window, you can reset your password. For more information, see Reset your Mac login password.