Unlocking Developer Options on other devices is pretty simple, you just go to about phone and tap Build Number 7 times. But in case of G3, it is pretty tricky. You don't see Build Number in About Phone. It is located somewhere else. But Where? Let's Find Out.
1) Open Menu and go to Settings.
2) Scroll down and go to About Phone.
3) Scroll down and tap Software info.
4) Now here you will see Build Number. Tap on it 7 times in order to become a Developer.
1) Open Menu and go to Settings.
2) Scroll down and go to About Phone.
3) Scroll down and tap Software info.
Remember once you unlock this option, you can only lock it again by resetting the device or by flashing ROM. Developer options are useful, using these options you can Master your device.