The Name Servers of a domain name show the DNS servers that manage its DNS records. The IP address of the site (A record), the mail server that handles the emails for a domain (MX records), any text record in free form (TXT record), directing (CNAME record) and so forth are obtained from the DNS servers of the hosting provider and for any domain name to be using them and to be pointed to their hosting platform, it needs to have their name servers, or NS records. If you would like to open a site, for instance, and you input the URL, the browser connects to a DNS server, which keeps the NS records for the domain name and the request is then redirected to the DNS servers of the hosting provider where the A record of the website is obtained, enabling you to see the content from the correct location. Usually a domain name has 2 name servers that start with NS or DNS as a prefix and the distinction between the two is only visual.