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 given host company for your domain address is the most convenient way to forward it to their system and all its sub-records will 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 would like to edit some of these records, you will be able to do it through their system. In other words, the NS records of a domain reveal the DNS servers that 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 want to access. This way the website that you will see will be retrieved from the correct location. The name servers usually have a prefix “ns” or “dns” and every single domain name has at least two NS records. There's no sensible difference between the two prefixes, so what type a host company will use depends exclusively on their preference.