There are a lot of DNS record types, at least 50 out there! One of them is called DNS TXT record, and it has a variety of purposes. Yes, it is one simple text record, but it is widely used, so let us explain the TXT record.
TXT record explained
TXT record is a DNS record type that has text information designed for external to the domain sources. The text could be written for people, so it would be easy to read, has enough information and logically organized, or made for computers, and has a more technical format.
Usually, you will see, inside the TXT record, a piece of general information about the domain and an additional part for a particular type of validation.