Easy 4 steps to Enable Developer Mode for android phone.

Follow the steps to enable Developer Mode:

1. Go to settings > About Phone
2. About Phone > tap 5 times on UI 
3. A message displays that “Now You are a developer”
4. Check-in settings > Additional Settings > Developer Options

Also helpful for some other tips Like, such as Connect Bluetooth Device, Cast Your Screen, Change Display Mode, Finger Print Lock.