Enable USB Debugging Mode on Android

USB Debugging grants you a level of access to your device. This level of access is important when you need system-level clearance, such as when coding a new app.USB Debugging Mode is a mode that can be enabled in Android after connecting the device directly to a computer with a USB cable. The primary function of this mode is to facilitate a connection between an Android device and a computer with Android SDK (software development kit).

1. Android 2.0-2.3.x

Settings > Applications > Development > USB Debugging

2. Android 3.0- 4.1.x

Settings > Developer Options > USB Debugging

3. Android 4.2.x and higher.

1. Go to "Settings".
2. Scroll down to the bottom and tap "About phone" or "About tablet",
3. Scroll down to the bottom of the "About phone" and locate the "Build Number" field.
4. Tap the Build number field few times to enable Developer Options. Tap a few times and you'll see a countdown that reads "You are now 3 steps away from being a developer."
5. When you are done, you'll see the message "You are now a developer!".
6. Tap the Back button and you'll see the Developer options menu under System on your Settings screen.
7. Go to Settings>Developer Options>USB Debugging. Tap the USB Debugging checkbox.

4. Android 5.0 Lollipop

1. Settings > About Phone > Build number > Tap it few times to become developer
2. Settings > Developer Options > USB Debugging

NOTE: To disable USB Debugging and other developer options when you don't need them, slide the switch at the top of the screen from On to Off.