Registering a domain and hosting one is frequently mistaken by a lot of people to be the same thing. They're in reality two different services - the domain name registration is the actual name and nothing more, while the hosted domains feature reveals the amount of already registered domains you can accommodate in the same website hosting account and have website files and emails for them. Your sites will work in precisely the same way no matter if the domain names are registered and hosted at the same place or are registered with company A and pointed to company B. Simply registering a domain name without hosting it will give you ownership, but will not enable you to have a site until you host this domain name in some account so that records for it are set up and it starts opening the information from that account.