It may be a simple on/off or, on some models, you can adjust the brightness of the backlighting. Enable “Keyboard lighting” and select the brightness you want. Click on the tab to access additional options. Move the slider under the “Keyboard backlight” tab to the right to enable the backlight. Open the Windows Mobility Center, and you will see a few options. How do I change my keyboard backlight settings?
If there's a Built-in Device Options menu there, you will find keyboard settings under it that allow you to set your backlit keyboard to always on.
Open your HP BIOS and go to the Advanced Settings tap.
