Personally, but some may disagree, if you're using Windows 10 and it's a gaming PC, and you're not downloading dodgy files, then the supplied Defender does the job.
You can download 3rd party Malware checkers - but i've only ever caught one virus on my system and that was thanks to my wife opening an attachment, years ago, from a friend unwittingly spreading a virus via some crappy meme.
But if you're not downloading from unknown 3rd party sources and sensible about what you open - you should be fine with the Window's security features.