Google made the Developer Options hidden starting with Android 4.2 so that average users wouldn’t accidentally change some system settings which would cause problems on their device. Most of the settings can be found easily, but advanced options are hidden under the Developer Options which Android enthusiasts and developers may want to tinker with.
Once you enable these Developer Options, you can do anything that require developer access and USB debugging. But just like Android 4.2 Jelly Bean, it is hidden for users and some taps here and there would easily enable it. Some might find this as an odd approach but that’s how Google thought to solve a problem, so that average users wouldn’t access it and developers can manually enable it if required.
Here’s how you can enable developer options in Nexus 5 or Android 4.4 KitKat. Just follow this simple procedure and you’re good to go.
Go to Settings > About Phone and then tap on ‘Build Number’ 7 times. Once you’re getting close to enabling this option, you’ll get a prompt that says “You are now 3 steps away from being a developer.” Keep tapping it. That’s all you need to do, and you’ll now have access to new developer options
You’ll now be able to enable the USB debugging and get to tinker with many more advanced options. Have fun with the new Developer menu option.