An add-on domain allows you to reach a subdomain when entering the name of the add-on domain into a browser. This means you can host additional domains from your account.
Before you begin adding domains into cPanel, you will need to complete Name Server changes first. Take those Name Servers and at your Domain Registrar's Control Panel and make the Name Server changes.
1. Click the Addon Domains icon under the Domains section.
2. Enter the new domain name.
3. Enter the directory name in your main account where this new domain will be pointing.
4. Enter a password for this new add-on domain.
5. Click on the Add Domain button.
That’s it! The new add-on domain has been created! A new FTP account has also been created for this add-on domain! Once the Name Server changes fully propagate, your add-on domain will be fully functional.