Why does the message I received show that I have read it?

Take Apple's mobile phone as an example. This is because "never preview information" is set in the mobile phone notification. The method of using this function is as follows:

Tool: iPhone 8

Operating system: iOS 14.4. 1.

1. Open the phone, find the "Settings" item on the desktop, and click Enter.

2. After entering the settings, find the "Notice" item and click Enter.

3. After entering the notification, find the "Information" item, and then click Enter.

4. After entering the information, find the item "Show Preview" and click Enter.

5. After entering the display preview, check the "Never" item, so that the message will not display the content.