1. Log in to your cPanel > Mail section > Email Accounts menu
2. If you have multiple domains, select the domain you want your email account to be associated with in the drop-down list in the top right corner and enter the desired email and a strong password of your choice
Click on Create Account once all is set.
3. To log in webmail, click on More next to the email account in question > Access Webmail
4. Once done, you will see the icons of the three webmail interfaces
5. Feel free to choose any access webmail, you can set roundcube as default