The NS, or Name Server records of a domain name, point out which servers manage the Domain Name System (DNS) records for it. Setting the name servers of a specific host company for your domain is the easiest way to point it to their system and all its sub-records are going to be handled on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), and so on, if you wish to change some of these records, you're going to be able to do it using their system. Put simply, the NS records of a domain name point out the DNS servers which are authoritative for it, so when you try to open a web address, the DNS servers are contacted to obtain the DNS records of the domain name you are attempting to reach. That way the website that you're going to see will be retrieved from the proper location. The name servers normally have a prefix “ns” or “dns” and every single domain address has at least 2 NS records. There is no functional difference between the two prefixes, so what type a website hosting provider will use depends completely on their preference.