The advice above is pretty spot on. In todays world of cyber security, 3rd party antivirus software is not needed. None of them are perfect, and windows defender is as good as any of them. Just make sure that you run windows update every couple of days to make sure you're current.
If you feel you must have a second layer of protection, download the free version of Malwarebytes. Make sure it's not running in the background, keep it updated, and do a periodic scan.
Defender is all you need for your everyday AV. Just be smart online and don't click on attachments, even from friends.