Turn your Mac keyboard’s backlighting on or off
If your Mac laptop has a backlit keyboard, you can manually adjust the level of backlighting or turn it off, or set options to do so automatically.
Manually adjust keyboard backlighting or turn it off
Do one of the following:
On all Mac computers: Choose Apple menu
in the sidebar. (You may need to scroll down.) On the right, drag the “Keyboard brightness” slider to adjust the brightness. Drag it all the way to the left to turn backlighting off.If your Mac has keyboard brightness keys: On the keyboard, press the increase brightness key
or the decrease brightness key 
. To turn backlighting off, keep pressing .If your Mac has a Touch Bar: In the Touch Bar, expand the Control Strip, then tap the increase brightness button
or the decrease brightness button . To turn backlighting off, touch and hold .
Tip: You can also adjust keyboard brightness right from the desktop by adding the Keyboard Brightness module to the menu bar or Control Center. Choose Apple menu > System Settings, then click Control Center 
in the sidebar (you may need to scroll down). Go to Keyboard Brightness on the right, then turn on Show in Menu Bar or Show in Control Center. To adjust the brightness, click the Keyboard Brightness icon in the menu bar or in Control Center.
Automatically adjust backlighting in low light conditions
Choose Apple menu
Turn on “Adjust keyboard brightness in low light” on the right.
Automatically turn backlighting off after a period of inactivity
Choose Apple menu
Click the pop-up menu next to “Turn keyboard backlight off after inactivity” on the right, then choose a time.
Tip: The light sensor is located at the top of your computer near the camera; make sure that area isn’t covered when you use your Mac in low light conditions.