Feel free to try them out and find the one you are most comfortable with.
Accessing your email through your favorite web browser
Type this into your browser:
You will be prompted to enter your username and password
For email accounts that you setup in your control panel
username: the full email address that you are trying to access (i.e., email@example.com)
password: the password that you choose when you set up this email account in your control panel.
For the default account that came with your account
username: the username for your hosting account (the same username you use to access your control panel; e.g. username not firstname.lastname@example.org)
password: the password for your hosting account (i.e., the same username you use to access your control panel).