Re: where is app for on galaxy note 4?
It's in the form of a widget, not an app (unless you download a third party app).
1. Tap and hold on an empty space on the Home screen until options appear.
2. Touch Widgets.
3. Navigate to, and tap and hold on, Torch.
4. Drag the widget on to the Home screen.
5. Touch the Back key.
6. Tap the widget to turn the torch on the back of your device on or off.