Your clients will need to access cPanel to allow them to setup e-mail addresses, access webmail, add or edit databases and manage their hosting account with you.
To solidify your brand, you can provide your clients with an unbranded URL. By default and without additional configuration, your primary domain name can be used.
http://www.example.com/cpanel or
http://www.example.com:2082
For WebMail access, your clients can use:
http://www.example.com/webmail or
http://www.example.com:2095
