In the first step, unlock your device. On any screen / application slide on the screen horizontally by single thumb. Good, now you should see your screen dividen in two sides. To resize move black line to the top or bottom. If you wish quit this mode move a line to the deep bottom of the screen. Perfect work!
How to Enable USB debugging on Huawei? If you want to use the AirDroid Personal Desktop Client to run a Non-Root setup or use the AirDroid Cast's USB feature to cast and control your Android devices, you should enable the USB debugging on your Android device first. XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. I recently upgraded from an iPhone to a Huawei Nova 3i, which is an excellent budget phone. One issue I have with it, is that there