How to make the software on the mobile phone horizontal?

Take OPPO A9 mobile phone as an example, the operation method is as follows:

1. First, you need to open the settings app on the mobile phone desktop, as shown below.

2. After entering the settings, select the display and source brightness options, as shown in the diagram of zhidao below.

3. After entering, find the automatic rotation function, as shown below.

4. Turn on the automatic rotation function, so that the software can operate horizontally.