Any "text free" apps that really you can use like real text or messenger, without having to pay for…

Any "text free" apps that really you can use like real text or messenger, without having to pay for it or watch videos or anything like that??? And if so could you tell me which one and maybe screenshot what it looks like. For android not Apple.

My baby daddy uses some dumb ass app because he doesn't have a phone service (and won't for a good while if I have anything to say about it)... He refuses to just get facebook messenger. He always claims he doesn't get my message or he has no credits and can't answer the phone etc. I swear there are tons of apps that are straight up free and not like this. But it's been AGES since I had anything like that and didn't just pay my phone bill like a responsible adult.