Report on sending short messages

As long as the other party's mobile phone is in the service area (with a signal) and has not been turned off, no matter what he is doing, as long as you receive your short message, you will immediately receive a short message to send a report, unless the signal is not strong, there will be some delay. You know, it was his mobile phone that received your message, and you received the information report, not that he read your message.