Any active domain that is added in a hosting account has a number of records that permit it to perform properly. In the common case, the name servers (NS records) show the location where the Internet domain is hosted and they are set on the side of the registrar company, but on the lower level there are certain records created through the hosting company such as A (IP address of the website/server), MX (e mail server), SRV (employing a domain address for non-website purposes on a particular port number such as Voice-over-IP), and so on. Having access to these records and by being in a position to edit them, you could have your site with company A and your emails with company B, for example. This gives you more freedom because you can pick the best provider for every single one of these services and you do not have to stick to one company. After you choose a hosting company, you have to make sure that you have access to all DNS records freely since some companies have an extra fee for this feature.