To turn on the USB debugging, you can use the following steps.
Go to “Settings” -> “My device”-> “Build number”.
Touch the Build number no less than 7 times.
Touch “OK” on the pop up window to allow development settings, you will see a warning that mentions that developer mode is already turned on.
Go back to “Settings” again, go to “System”; you will now find the “Developer options”.
“USB debugging” option is enabled by default.
Note: Available settings and menus may vary depending on device model and software version.