Do I have to be friends with others to send a message by fetion?

Yes, you must be friends. But if the other party doesn't open Fetion, you only need to send a request to add him as a friend in Fetion, and the other party will receive a short message to add him as a friend. As long as the other person replies to you, you can add him as a friend, send him a short message in Fetion, and surf the Internet for free. The other party replied to you by text message, not by charge.