If I add a friend and the other person is not online, can he receive the text message if I send him a message with Mi Chat? If so, is this message free or not? ...

If the other party is not online, he should be able to see the message you sent by logging in to Mi Chat again, which should be the same as qq! I haven't used it. I don't know the details! If the software needs network operation, then there is no charge, and the deduction should be traffic, so it is no problem to make a monthly subscription! Mi Chat is similar to WeChat, right? It should be!