Domain Names
Creating an add-on domain (flash tutorial)
Parked domains allow a user to part or point a domain name to their account. This will allow the parked domain name to act and work just like the master domain name on the account. It will seem as if it's the same site, but under a different domain names. Many users do this with all of the major TLDs (Top Level Domains). So for instance if a user has domain.com registered and they wanted the .net and .org pointing to the .com and working the exact same way. They would use the parked domain section to achieve this. Each domain name would act just like the other, just under a different extension.

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Simple add the domain name that needs to be parked and hit “Add Domain!” It's that simple. Remember to update the DNS on any domain names being added. Once a domain name is added it can be viewed from the same location. Users will be able to remove a domain name once it has been added also.
Addon Domains
Add-on domain names are very similar to “Parked Domains”, but they use their own account. Users use these often when start another web site, or hosting a site for a friend of family. Be sure to check to make sure that access to this is available and that there are enough add-on domain name slots available. This is visible from the front page of cPanel.
1) Type in the new domain name.
2) Type in the username, directory, or sub-domain the new domain name will be using.
3) Type in a password.
4) Hit Add Domain!
That's it, once all the above is completed a new domain name and account has been added. This user or account doesn't have access to cPanel, so don't worry about that. They will have FTP access and a new email address if all that is setup in the correct areas. We'll explain that later on.