Registering a domain and hosting one is often mistaken by a lot of people to be the same thing. They're in fact 2 different services - the domain registration is the actual name and nothing else, while the hosted domains feature reveals the number of already registered domains that you can accommodate within the same hosting account and have website files and emails for them. Your websites will function in exactly the same way no matter whether the domain addresses are registered and hosted at the same place or are registered with company A and pointed to company B. Simply registering a domain address without hosting it will grant you ownership, but will not enable you to have a website if you don't host this domain address in some account so that records for it are created and it starts opening the data from that account.