How is it that there is a "sent" SMS reply after each SMS?

That's the problem with your mobile phone settings, that is, it is set to "receive information report", so that whenever the other party receives your information, the operator will reply you with a face fee prompt-"sent". You can cancel this service in phone settings or SMS settings. Turn on this function to know more accurately whether the other party has received your message. But mainly depends on the user's personal hobbies …