Night Shift "automatically shifts the colors of your display to the warmer end of the color spectrum after dark," according to Apple. This will allegedly help you sleep better, and it is useful in dark places like the movie theater where you do not want to use a bright screen.
There are three ways to enable Night Shift on your device (iOS 11 and later):
- Swipe up on your Home screen to open Control Center. Perform a hard press on the brightness slider. Select the Night Shift option.
- Navigate to Settings > Display & Brightness > Night Shift then tap "Manually Enable Until Tomorrow."
- Navigate to Settings > Display & Brightness > Night Shift and select the "Scheduled" option to schedule a time for Night Shift to automatically enable itself.