The NS, or Name Server records of a domain name, show which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a given host company for your domain name is the simplest way to direct it to their system and all its sub-records are going to be taken care of on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), etcetera, so if you would like to edit any one of these records, you are going to be able to do it via their system. To put it differently, the NS records of a domain name 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 domain name you are attempting to access. In this way the site that you're going to see is going to be retrieved from the proper location. The name servers normally have a prefix “ns” or “dns” and every single domain name has at least two NS records. There isn't any practical difference between the two prefixes, so what type a host company is going to use depends completely on their preference.