Having 100 % control over your domains is something rather important and being able to access and edit the DNS records for each of them is one of the things you should look for when you search for a registration or a hosting provider. You may have heard about the so-called “name servers” that show where a domain address is hosted, but below them there's a whole list of records, such as the A record, which is the IP address of the server hosting the site, and the MX records, which show the server that manages the emails for a particular domain address. These records are used if you wish to have your site with one company and the emails with another, for instance. Additionally you can use a domain address for a non-website service or forward the traffic to it by using special records. A lot of companies ask for an additional fee to grant access to edit specific DNS records besides the name servers.