To change your email account passwords, use these steps:
1) Log into your account dashboard.
2) On the left-hand side, expand the "Hosting" section, and then choose "My Hosting".
3) Click the "Login" icon (a picture of a person) to the right of your hosted domain name.
This takes you to your hosting control panel, or "cPanel".
4) Go to "Email Accounts"
5) Locate the account that needs to have it's password changed, and click "Change Password".
6) Enter in the new password twice to confirm.
If you already know the password, it can be also changed at http://[domain]/webmail or http://webmail.[domain]/.