cPanel is a web hosting account management tool available on all Dotcom Igloo Linux hosting plans.
You only get one username per cPanel. If you create addon, parked and subdomains, those domains can be accessed by logging in to your main cPanel; you will not have a separate cPanel or separate login credentials.
The username and password to log into cPanel can be found in your welcome email. If you do not have the correct login credentials, please submit a support ticket and we will send it over.
You can always find your cpanel link by typing /cpanel after your domain name, i-e: yourdomain.com/cpanel