Is it free to send short messages to offline users? Can it be like Fetion, the other party didn't log in to Fetion, but the text message arrived at the mobile phone?

Mi Chat sends messages to users who are not online. Only when the other party logs in to Mi Chat can they receive it. When the other person reads your message, you can see the words you read. If the other party is not logged in, you will see the message.

Mi Chat transmits information by traffic, and the charge of traffic depends on your mobile phone tariff.