Each registered domain name has no less than two Name Server records that show where it's hosted i.e. by using these records you direct your domain address to the servers of a particular website hosting company. This way, you have got both your site and your emails handled by the exact same service provider. On the lower level of the Domain Name System (DNS), nevertheless, there are a number of other records, like A and MX. The first one shows which server handles the site for a given domain and is always an IP address (18.104.22.168), while the latter reveals which server manages the e-mails and is always an alphanumeric string (mx1.domain.com). For example, whenever you enter a domain address in your browser, your request is forwarded through the global DNS system to the company whose NS records the domain name uses and from there you will be sent to the servers of a different company if you have set an IP address of the latter as an A record for your domain. Having independent records for the site and the emails means you can have your site and your e-mails with 2 different providers if you wish.