Registering a domain and hosting one is usually mistaken by many people to be the same thing. They're actually two different services - the domain registration is the actual name and nothing else, while the hosted domains feature shows the amount of already registered domain names that one could accommodate in the same web hosting account and have website data and email messages for them. Your sites will work in precisely the same way no matter whether 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 name without hosting it will grant you ownership, but will not allow you to have a site if you don't host this domain in some account so that records for it are set up and it starts opening the data from that account.