Turns out I didn't send the text message myself. What does the software look like?

You can download a 360 mobile phone guard or security housekeeper. Both of these softwares have the function of sending flash messages. In other words, if you send it, it will be displayed automatically, and the recipient doesn't have to press anything. But once he finished reading the message and closed the page. The text message you sent will never be found on his mobile phone. I tried. Very interesting! The tariff is the same as the SMS sent in peacetime! Ha-ha，，，