Webmail is a cPanel function – but you don’t have to log into cPanel to use it – and it can be used for a number of reasons:
Here’s how. Open a browser window and go to http://www.yourdomain/webmail/, where “yourdomain” is your domain name. Log in to your mailbox with your full email address and mailbox password. If you’ve entered a valid email address and the correct mailbox password, you’ll be presented with a landing page like this, and you can choose any of 3 programs to read & reply to messages, reset your mailbox password or manage your auto-responders.
If you can’t log in, your mailbox password may not be what you thought it was, and you’ll need to reset it via cPanel > Mail > Email Addresses.