Use the brightness keys on the keyboard
Press the Fn key plus the brightness-down key
Open Settings and lower the display brightness
Use the Action Center or Quick Settings brightness slider
Adjust brightness from the battery or power menu
Turn on battery saver mode if available
Update or reinstall display drivers if brightness controls do not work
Use the monitor controls if using an external display
Reduce brightness through the graphics control panel
Check if adaptive brightness is enabled and disable it if needed