The NS, or Name Server records of a domain name, indicate which servers deal with the Domain Name System (DNS) records for it. Setting the name servers of a specific hosting provider for your domain address is the simplest 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 need to change some of these records, you will be able to do it through their system. Put simply, the NS records of a domain reveal the DNS servers which are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to retrieve the DNS records of the Internet domain you are trying to access. This way the website that you're going to see will be retrieved from the right location. The name servers normally have a prefix “ns” or “dns” and each and every domain has at least 2 NS records. There is no functional difference between the two prefixes, so which one a web hosting provider will use depends entirely on their preference.
