The NS, or Name Server records of a domain name, reveal which servers manage the Domain Name System (DNS) records for it. Setting the name servers of a particular host company for your domain name is the most convenient 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 need to edit any of these records, you will be able to do it using their system. To put it differently, the NS records of a domain show the DNS servers that 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 domain name you are trying to reach. That way the website you will see is going to be retrieved from the right location. The name servers normally have a prefix “ns” or “dns” and each domain address has at least 2 NS records. There is absolutely no practical difference between the two prefixes, so what type a website hosting provider is going to use depends exclusively on their preference.