Hello, this is Emily.
Keyboard backlight is actually not a Windows feature, but a hardware feature. It also depends on if your model should come with this feature. Has it worked in the past?
If your model should come with the keyboard backlight, typically you can find the key to control the light among the function keys on the top row. If you can't find it, it is possible that your model is not equipped. I can help you look it up but need some info about your device. Please type msinfo32.exe in the search on the taskbar and hit enter, then share a screenshot of the pop up please.