To change a password on behalf of a user, first sign on or "su" to the "root" account. Then type, ``passwd user'' (where user is the username for the password you are changing). The system will prompt you to enter a password. Passwords do not echo to the screen when you enter them.
You can also change your own password, by typing ``passwd'' (without specifying a username). You will be prompted to enter your old password for verification, and then a new password.