Keychain will work well for a Mail password recovery. Simply use spotlight and type in keychain then press return (spotlight is located in the upper right corner of the screen and looks like a magnifying glass). Find the name of the mail account and double click or tap on the appropriate entry. The very bottom of the entry will have a box that reads "show password", click on that box. You will then have to authenticate using the computer account credentials (the user name and password you use to log in to that account on the computer). Once authenticated the computer will show you the password needed.