There's a wide range of ages when it comes to the Roblox generation and I speak from experience as a librarian having to shush both kids and teens for being too loud on the computers while playing.

You can use Google Chat to message anyone, as long as you know their name, email address, or phone number.

You can play iMessage games on your iPhone using the App Store extension that's built into iMessage. There, you can download a variety of games.