How does oppoReno5Pro know where the other party has read the text message?

1, first open the settings in the phone.

2. Then drop down in Settings, find the message after the drop down, and click Open.

3. After opening, select Send Read Receipt and click the button at the back.

4. When the button behind the sent read receipt turns green, it will be turned on, so that texting others will show that it has been read.