The NS, or Name Server records of a domain name, reveal which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a given hosting provider for your domain is the most convenient way to forward it to their system and all its sub-records are going to be managed on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), etcetera, if you wish to change some of these records, you will be able to do it using their system. Put simply, the NS records of a domain address point out the DNS servers which are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to get the DNS records of the Internet domain you are trying to access. This way the website that you're going to see is going to be retrieved from the correct location. The name servers usually have a prefix “ns” or “dns” and every single domain name has at least 2 NS records. There's no functional difference between the two prefixes, so what type a website hosting provider is going to use depends entirely on their preference.