NS records, or name server records, define which authoritative name servers contain the DNS records for a domain.
You can use NS records to delegate DNS queries between multiple DNS providers for a domain or subdomain. For example, if you purchase a domain through GoDaddy.com but want to manage your domain’s DNS records using DigitalOcean, you need to edit the NS records for your domain at GoDaddy.com to indicate that DigitalOcean’s name servers are the authoritative servers for your domain’s records.