Any time you add a domain as hosted in some account, you normally set a pair of Name Servers to direct it to that particular provider. On their end, three records are set up automatically the moment the domain name is added - one A record and two MX records. The first one is a numeric address, or IP address, that “tells” the domain name where its site is, while the other two are alphanumeric and they show the server that deals with the emails for that specific Internet domain. The website and the e-mail hosting are typically considered to be one thing, while they're in fact two different services. Having different records for them will allow you to have them with different providers if you'd like. As an illustration, some new company might have outstanding uptime for your website, but you might not want to switch your e-mail messages from your current host and by using an A record to point the Internet domain to the first and MX records to have the emails with the second, you can get the best of both companies. These records are checked whenever you want to open a website or send an email - in any case, the provider whose name servers are used for the domain is going to be contacted to retrieve the A and MX records and if you have set records different from their own, the correct web/mail server will then be contacted and you'll see the needed website or your e-mail will be delivered.