Why does the mobile phone display the phone receipt number when texting?

The reason for asking for this number is to confirm whether the short message was sent successfully, so that the receiver can reply to the short message conveniently.

When the user sends a short message, the mobile phone will generate a phone receipt number, which usually consists of 10 digits. This number is sent to the receiver together with the content of the short message. When the receiver receives the short message and replies, it needs to input the phone receipt number in order to send the replied short message to the correct receiver.

In addition, the telephone receipt number can also be used to confirm whether the short message was sent successfully. If the receiver does not receive the telephone receipt number, he can send a short message to the designated number to confirm whether the original short message was successfully received.