Java script quesion.

How do you make a script that sends messages to a specific person that has the app that who are on the user's list?

What I mean is that I'm looking for a way to make a button that will send something to the other user on that person's list, "do you want to hangout?" or an alternative that allows the person asking to write a custom message to the person's list and once sent the other person will recieve it and it can respond back respond with a preset button of yes, a no button or a custom response that goes back to the person asking.

This is for aperyio btw