The TXT records is source registrations in DNS, which may contain random text and can also be used to determine machine readable text.
More frequent use of TXT records is to verify the ownership of a domain.
Also, you may need to use TXT records to prevent violation methods of your email, such as SPF, DKIM and DMARC.
The TXT records are stored by the registrar of your domain and therefore can be changed in association with him.
The advantage of TXT records is that you can fill it with whatever text you wish.
For example, you can have a TXT record with value google-site-verification=rXOxyZounnZasA8Z7oaD3c14JdjS9aKSWvsR1EbUSIQ, which can be used to verify the ownership of a domain, to activate the Google Apps.
