What should I do if Huawei p20 mobile phone locks the screen and does not display the message notification content?

This is because there is no setting to display content in the screen lock state.

Huawei P20 mobile phone opens the lock screen and displays the following contents:

First, click "Settings" on Huawei P20 mobile phone desktop.

Second, after entering, select the "notification and status bar" information.

3. Then click "Notification Management" to enter.

Fourth, after entering, find the content displayed by the application. Here, take information as an example.

5. After inputting the information, just turn on the switches such as "Display on Status Bar", "Banner" and "Display on Lock Screen".