Why send text messages on Android phones? Some messages are selected and some messages are not displayed.

It's time for you to open the SMS to wake up. In other words, if the other party receives your message, you tick here. If the other party does not receive it, it will not be ticked. (Of course, the specific mobile phone brands are different, and the labeling methods are different. Some are ticked and some are text reminders. For example, if you send a text message, the other party's mobile phone is turned off. After you send it successfully, don't check the back. When the other party turns on the phone and you receive this message, you will check it on the phone. However, due to the multiple influences of operators, the receipt is not very accurate and reliable. Hope to adopt!