Registries and registrars usually charge an annual fee for the service of delegating a domain name to a user and providing a default set of name servers. Often, this transaction is termed a sale or lease of the domain name, and the registrant may sometimes be called an "owner", but no such legal relationship is actually associated with the transaction, only the exclusive right to use the domain name. More correctly, authorized users are known as "registrants" or as "domain holders".
That said, not all web hosts offer email. WP Engine, for example, does not. In such instances, you must email accounts from a company other than your web host. GoDaddy, for instance, sells email packages starting at $3.49 per user, per month. That might sound like a hassle, and just one more thing to keep track of, but there are actually some webmasters who feel that separating your email hosting and web hosting services is smart. That way, one provider going offline won't completely bork your business.
For those users who are seeking to register a country-specific domain name option (like “.us” or “.co.uk”), a good portion of the registration process will be dedicated to determining whether or not the customer is a resident of that country and therefore legally permitted to purchase one of its country-specific top level domains (will talk about this later). And that should hammer home a secondary point to users.
Moving to another website consists of transferring the website’s files and databases, configuring your site with the new host, and directing your domain’s DNS to the new host. Once you pick a new site host, they can usually help you out with this process. The cost will depend on the host you’re switching to, but it will probably be anywhere from $150-$400.