How do you invite someone? ? On this game
You can’t, but you can let them download the same game from the Play/App store.
To be friends, make sure you are on the same server (Main menu --> hero portrait --> scroll down --> accounts) and say something in global chat. Then the other person can click that message and send a friend request.
If you want to, you can then also search for and join the same guild on that server (but just make sure you’re on the same server).