You can login to cPanel by :
http://cpanel.yourdomain.com
http://yourdomain.com:2082
http://yourdomain.com/cpanel
https://yourdomain.com:2083 [ SSL ]
You can login to WHM Panel by :
http://whm.yourdomain.com
http://yourdomain.com:2086
http://yourdomain.com/whm
https://yourdomain.com:2087 [ SSL ]
You can login to WEBMAIL by :
http://yourdomain.com/webmail
=============================
You can also replace yourdomain.com with your server IP too for login !