I opened Fetion. How to send text messages to people who haven't opened Fetion?

It depends on the software downloaded by your mobile phone model. Some mobile phone model software shows users who have not opened Fetion. You can send it to them. If your mobile phone software does not show the user who has not opened Fetion, you can only send it to him by computer. "The other party has not opened Fetion service" can also be added as a friend. Fetion stipulates that more than 5,000 text messages cost 10 cents a month, but I believe you don't need 5,000 text messages, so it only counts.