Android USB debugging mode simply facilitates a connection between an Android device and a computer. You must enable the feature on your Android device before you can do anything on your phone when connected to a PC. While the feature is available by default on some devices, it is hidden by default in some devices running on Android 4.2 and newer.
On my Tecno M7, the USB debugging mode is not hidden by default despite the fact that the Android-powered handset is running on Android 4.2.2. Before you can enable it on Android Tecno M7, you must first turn ON the “developer options”.
To switch it ON, go to “Settings”, scroll down and tap on “developer options”. Then slide it to “ON”. Thereafter, you can scroll down and select “USB debugging”. You will see a confirmation prompt. Tap “OK”.
You can then connect your Tecno M7 to your computer using a USB cable to do whatever you want to do with it on PC.
NOTE: It’s best to keep USB Debugging Mode disabled and only enable it when you really need it.