TXT records are custom records that contain machine-readable data. TXT Records must be formatted according to the technology you wish to use. TXT records are a type of Domain Name System (DNS) record that contains text information for sources outside your domain. You add this record to your domain settings.
You can use TXT records for a variety of purposes. Google uses it to verify domain ownership and to ensure email security. When you set up your Google G Suite or Google Cloud account, Google gives you a note to add to your domain settings. When Google sees that you've added a record, your domain ownership is confirmed.