Any possibility of texting offline(data as well but I'm ok if it needs data)?

So I wanna by my girlfriend a phone because her mom won't let her cause she believes that drama will be back and she doesn't want to listen to it. 
Main Question: So is there a way to communicate with my girlfriend without WiFi.  

Linda2019-10-25T15:20:22Z

There is no way to communicate unless you talk face to face or talk on the home phone or landline, providing she has that. Maybe you can persuade her parents to let you buy her a phone if they know you'll be responsible for the monthly phone bill.