Scroll down to the bottom and tap the About Phone option.
Scroll down to the bottom on the About Phone screen. You will see option Build Number.
Tap seven times Build Number option. After three taps, it will display a message such as, "You are now 2 steps away from being a developer". After tapping seven times, it will display a message that "You are now a developer".
Go back to Settings and scroll down to the bottom. You will see option Developer Options above About Phone.
Connect your device with PC using USB cable.
Go to Settings > Developeroptions.
Select Enable the USB Debugging option. A pop-up is displayed asking confirmation about switching on USB Debugging.
If you are using device manufactured by Xiaomi, you must select must enable the USB Debugging(Security settings) option.
Click OK.
Note
When you connect device to the computer, system asks for permission to allow USB debugging. Select the check box, Always allow from this computer and then click OK.
