DNS resource records are primarily a massive collection of IP addresses of domain names, services, zones, private networks and devices used by DNS servers to locate services or devices on the Internet worldwide, and are inherent to the functionality of the Internet. DNS servers then translate the numerical IP addresses from the DNS resource records into user-friendly alphabetic names that humans can easily remember.
The common metaphor used by experts to describe this protocol is that it's the phone book of the Internet. Internet devices generally use numeric IP addresses to communicate with each other. Without a Domain Name System record, people need to remember and type the numerical IP addresses of websites or devices into their Internet browsers to access a service or device. DNS servers are responsible for mapping domain names and assigning numerical IP addresses, and they update the resource records several times in a day.
There are several types of DNS resource records, and each serves a different function. Each record type is categorically assigned to a specific DNS server that's also categorically assigned by the Domain Name System a specific class of service. The protocol is designed in this way to avoid DNS server-request congestion that can slow down Internet traffic.