You probably shut down your computer when you're done using it at the end of the day, but if not, you can set it to shut itself down on a schedule. This is easy to do with Windows Task Scheduler: ...

I’m going to let you in on a secret: I don’t really shut down my computer. When I’m done with my workday, I usually just unplug my laptop and close the lid. I think most people do this.

Some apps you may already have on your computer do double duty—they'll complete a task while you're off doing other things and shut down your system when they're done.