Each domain that is registered and hosted has quite a lot of DNS records - some of them are created automatically when you host a domain, others can be set up manually if necessary. As an illustration, the A record of a domain is its IP address i.e. this record reveals where the website is located; the MX records reveal where the emails are handled, while using an SRV record you can use a domain for unconventional purposes, for instance a Voice-over-IP service. The ability to create and modify certain records permits you to have different services with different providers if, for illustration, your present host provides dependable web hosting, but has troubles with the email service, or you simply prefer to get a specific service from a specific company. Although you must be able to create and edit these records freely and without any limitations as you own a given domain name, many companies charge extra to give you this option.