On a touchscreen, you can also swipe in from the right side of your screen to open the Action Center. Click (or touch) and drag the slider to adjust your screen’s brightness. If you don’t see the slider, click the “Expand” option above the grid of tiles. To access it, click or tap the notification bubble icon that appears to the right of the clock on the taskbar.
On Windows 10, you can find a quick brightness slider in the Action Center.
