Which app should I use?

[gloriousnumber1]

I am looking for an app (free is possible) that will let me text over wifi when I don't have voice coverage. I want to be able to do this without using an alternate number and without the person I text needing to download the app.

I would even pay for an app like this. There are so many out there.

Ideas, smart people?

 

[gloriousnumber1]

I think at the moment Kakao talk is the top

It also allows free voice calls over Wi-Fi.

Do I need to make an account to use it?