Use Night Shift on Mac
Use Night Shift to adjust the colours on your display to the warmer end of the colour spectrum. Warm screen colours are easier on your eyes when you use your Mac at night or in low-light conditions. Also, exposure to bright blue light in the evening can make it harder to fall asleep.
Note: To find out if your Mac supports Night Shift, see the Apple Support article Use Night Shift on your Mac.
Schedule Night Shift to turn on automatically
On your Mac, choose Apple menu
, then click Night Shift.Click the Schedule pop-up menu, then choose an option.
Off: Choose this if you don’t want Night Shift to come on automatically.
Custom: Choose this to specify the times you want Night Shift to turn on and off.
Sunset to Sunrise: Choose this to use Night Shift from sunset to sunrise.
If you select this option, your Mac uses your location to determine when it’s night-time for you. To use this option, you must turn on Location Services. Choose Apple menu > System Preferences, click Security & Privacy
, then click Privacy. Select Location Services, click the lock to allow changes, then click Enable Location Services, scroll down to System Services, click Details, select Time Zone & System Customisation, then click Done.
Turn Night Shift on and off manually
Even if you set a schedule for Night Shift, you can turn it on or off at any time — for example, if you’re in a darkened room.
On your Mac, choose Apple menu
Select Manual to turn on Night Shift.
Night Shift remains on until the next day or until you turn it off. To turn it off, deselect Manual.
Tip: You can also turn Night Shift on and off using Control Centre. Click Control Centre 
in the menu bar, click Display, then click the Night Shift button. You can also ask Siri to turn it on or off for you.
Set the colour temperature
On your Mac, choose Apple menu
Drag the slider to change the colour temperature Night Shift uses.