I would like to know if the following mobile operation systems: IOS, Android, Windows are allowing apps to make a DNS TXT record request.
I am planning to add some information in a TXT record that will be updated from time to time and would like to build an app that will read that.
Yes it can, there’s an app that does that even: https://play.google.com/store/apps/details?id=com.kodholken.dnslookup
However, I think your real question is not “Can a DNS TXT record be read by an app?” but rather “How?”, for that I have no answer as I’m not a network expert.