ALT + Print Scrn takes a screenshot of your active window (i.e. the game) handy if you have more then 1 monitor that way it doesn’t capture your second monitor. This only copies the pic to your clipboard. Thus you have to paste it into Paint, for example, and then save it off.
If you want to save the pic right away use WIN + ALT + Print Scrn. This saves it, by default, to \My Videos\Captures. This is using the Game Bar built into Win 10. If you want to record a video you can use WIN + ALT + R to start/stop recording. Save location is the same as screenshots. Press WIN + G if you want to get to settings to modify anything.
If you have GeForce Experience you can use ALT + F1 to save a screenshot. And ALT + F9 to start/stop recording. Use ALT + Z to get to the setting if you want to modify anything.