Shift to warmer colours manually on your Mac
Use Night Shift to manually 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. You can turn Night Shift on or off at any time — for example, if you’re in a darkened room.
Note: To find out if your Mac supports Night Shift, see the Apple Support article Use Night Shift on your Mac.
On your Mac, choose Apple menu
in the sidebar. (You may need to scroll down.)Click the Night Shift button on the right, then turn on “Turn on until [time]” option.
Night Shift remains on until the next day or until you turn it off.
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 use Siri to turn Night Shift on or off.