Registering a domain and hosting one is usually mistaken by a lot of people to be the same thing. These are in fact two separate services - the domain registration is the actual name and nothing more, while the hosted domains feature reveals the amount of already registered domain names which you could accommodate in the same hosting account and have site data and emails for them. Your websites will function in exactly the same way regardless if the domains are registered and hosted at the same place or are registered with company A and pointed to company B. Simply registering a domain without hosting it will grant you ownership, but will not allow 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.