Registering a domain and hosting one is usually mistaken by a lot of people to be one and the same thing. They are actually two separate services - the domain address registration is the actual name and nothing more, while the hosted domains feature refers to the amount of already registered domain addresses which you can accommodate in the same website hosting account and have website files and emails for them. Your sites will function in exactly the same way no matter if the domain names are registered and hosted at the same place or are registered with company A and directed to company B. Simply registering a domain address without hosting it will give you ownership, but will not enable you to have a site unless you host this domain in some account so that records for it are set up and it starts opening the data from that account.