Anti-Virus and Malware tools
For information about how to clean malware from your computer, or prevent it in the future, see this malware guide
AV - Anti-Virus runs constantly in the background, scanning files on download, on access, or on a schedule
AM - Anti-Malware should be run on demand to check for residual PUPs or other issues.
PUP - Potentially unwanted program, this is a generic term for 'shitware'
The built in solution for AV in Windows 10 is more than adequate for consumers. This is much better than running a free AV suite that is of lesser quality or plans to sell your personal habits for profit (MCafee, Avast, AVG, etc)
All free alternatives are considered shitware. They will sell you as their product and provide more a more troublesome experience. We do not recommend Avast, AVG, Kaspersky, McAfee or any other alternative AV.
Paid AV Suites
We do not recommend any paid AV suite for consumers, they do not provide significant advantages over Windows Defender and only increase overhead.