TXT is a DNS record, that contains info in human-readable form for external sources to obtain information regarding a certain domain or subdomain. In the most common scenario, this kind of record is employed to prove that you own a domain if you're trying to add it to a search engine or to some web traffic analytics platform. Considering that only the Internet domain owner/administrator is able to add custom DNS records, the TXT record works as a proof of ownership for the company supplying the service. Another popular use for this kind of records is the email SPF (Sender Policy Framework) protection, which ensures that an e-mail address will not be spoofed and that others will not receive unsolicited mail from allegedly your mailbox. The TXT record contains info about the mail server where your online messages come from and serves as validation that it's a reliable one. Since there are no regulations about the content of such a record, you can add any other information as well.