Student commutation app

Here we go: The classic one. I have an idea for (maybe) an app. But I have no idea if it’s possible. I got first graders. We use iTunes U a lot. But the really can’t get their heads around asking questions within the app...therefore: can I create a SIMPLE ‘chat/communication’ app that allows the children to write me messages...? So when they are in the other end of the school simply tap the app to write me a message...? And vice versa...? A must is notifications regards johnny