If you wish to Add Another Separate domain into cPanel, there is an option called Addon Domains. Login to your cPanel > “Addon Domains”.
After that Fill in your domain name in the domain name section without www.
Don’t fill subdomain and Document Root. Because it will be auto-filled itself when clicking on somewhere else.
After that press the Add Domain button.
Document Root is the Folder of you must upload your website. It should be in cPanel > File manager > “example.com”. Upload your all website files to the inside of example.com folder.
After that, Update Nameservers on Domain Name.
Update:
This Addon Domain option was removed from cPanel version 106.0.1. Please follow this article to add another domain name to a cPanel.