To reach the Web Mail feature for your account, simply type in:
http://webmail.yourdomain.com
(Replace yourdomain.com with the appropriate domain name of your account.)
Or, follow these steps to get to the Webmail program properly:
Login to your cPanel control panel.
Click on Email Accounts (under EMAIL).
Click the Check Email button next to the address you want to check.
On the next screen, it may show you program options (like Round Cube). Click the Open button to open the program.