Whenever you add a domain as hosted in some account, you typically set a pair of Name Servers to direct it to that specific company. On their end, three records are set up automatically when the Internet domain is added - one A record and two MX records. The former is a numeric address, or IP address, which “tells” the domain where its website is, while the other two are alphanumeric and they show the server that manages the emails for that specific Internet domain. The website and the e-mail hosting are often perceived as one thing, while they are in fact two different services. Having independent records for them will permit you to have them with different providers if you would like. For instance, some new provider might have exceptional uptime for your website, but you may not want to switch your emails from your current host and by using an A record to point the domain to the former and MX records to have the emails with the second, you can get the best of both providers. These records are checked whenever you want to open a site or send an e-mail - in any case, the provider whose name servers are used for the domain address is going to be contacted to retrieve the A and MX records and if you have set records different from their own, the right web/mail server will then be contacted and you are going to see the needed website or your e-mail is going to be delivered.