Your device will flash the camera light or the screen when receiver notifications or when alarms sound, when “Flash notifications” feature is enabled.
Please go to “Settings”->“Accessibility”->“Flash notifications”, touch the toggle switch to turn it on or off.
Enabling the Notification Flashes feature is extremely useful for people who usually check their device in a noisy environment where they cannot hear a notification, or for differently abled people with improper hearing.
Note: Available settings and menus may vary depending on device model and software version.