An addon domain is the option used to host different, additional domains on one hosting account each with their own distinct content and upload location (HTDOCS) folder.
From an end client point of view, an addon space capacities like some other area in that the site acts and is basically, totally separate from another site and as a result is totally extraordinary.
Before you can add a domain to your hosting account you must first change the nameservers of the domain via your domain registrar control panel to:
ns1.freehostingtrust.com
ns2.freehostingtrust.com