You can change your email password using the webmail system

1.) Point your web browser to: https://login.secureserver.net

Log in with your email address and current password.

2.)  Click on Email->Settings->Personal Settings

3.) Complete the fields on the "Security" tab

Make sure to enter a new password that is strong and not easily hacked. Refer to this article for more information: Setting A Good Strong Password

4.) Click OK

5.) Done