The USB debug mode is turned on under Android and there are three different methods depending on the system version, as follows.
Open USB Debug mode under Android 2.1-2.3.7 system
First click on the desktop settings, or press the phone button, choose to set this
In the set menu of the application of this item, there will be USB debugging items, tick
Open USB Debug mode under Android 4.0-4.1.2 System
Also click on the desktop settings, or press the phone button, choose to set this
USB Debug mode is in Developer's option
Open USB debug mode on Android 4.2 + above system
Also click on the desktop settings, or press the phone button, choose to set this
The options are on the phone.
In the inside even a few seven times version number, if it is a picture, click the build number seven times
Go back to the Settings menu and go to the developer option
There will be a switch on the upper right corner, open it.
When you open it, Root does the other thing.