The NS, or Name Server records of a domain, show which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain 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), and so forth, so if you would like to modify any of these records, you're going to be able to do it by using their system. In other words, the NS records of a domain address 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 attempting to access. That way the website you will see is going to be retrieved from the correct location. The name servers typically have a prefix “ns” or “dns” and each and every domain has at least two NS records. There's no sensible difference between the two prefixes, so what type a host company is going to use depends solely on their preference.