Every registered domain name has no less than 2 Name Server records that show where it is hosted i.e. by using these records you point your domain address to the servers of a specific website hosting provider. That way, you have got both your website and your e-mails managed by the exact same service provider. On the lower level of the Domain Name System (DNS), nevertheless, there is a variety of other records, for instance A and MX. The first one shows which server deals with the site for a given Internet domain and is always an IP address (18.104.22.168), while the latter reveals which server handles the e-mails and is always an alphanumeric string (mx1.domain.com). As an example, whenever you enter a domain name in your web browser, your request is directed through the global DNS system to the provider whose NS records the domain uses and from there you will be sent to the servers of another provider in case you have set an IP address of the latter as an A record for your domain. Having separate records for the website and the e-mails means that you can have your website and your emails with 2 different companies if you'd like.