Questions regarding the use of "anti-virus" or similarly categorized "Internet security" products frequently arise on this site. Many of them are from new Mac users whose previous computer experience was limited to traditionally virus-prone Windows PCs. Early Microsoft Windows versions were notoriously vulnerable to unauthorized modifications and malicious interference, which gave rise to a cottage industry of "anti-virus" software companies responding to a need for the operating system security Microsoft neglected to provide.
Apple and Microsoft's respective operating systems were originally conceived and developed completely separately, for use with completely different hardware, and their evolution has only diverged since their inception. In recent years Microsoft has made great strides in protecting its Windows operating system, but owing to macOS's original concept as a multi-user, multitasking operating system incorporating a fundamental requirement to keep users separate from one another, it was never as vulnerable to begin with. With each new release, macOS has only grown more secure from unauthorized tampering.
It's important to understand the nature of threats that exist today, and to appreciate the fact that "anti-virus" software peddlers have been reduced to abject panic as their traditional Windows PC market suffers its inevitable decline. The cottage industry described in the first paragraph has since grown to a multi-billion dollar behemoth with entrenched interests—an enormous beast that demands to be fed. The PC market's demise has led to a predictable response from them and shills who represent their interests, asserting that since Macs are rapidly growing in popularity, they have become just as vulnerable to "viruses" as PCs, implying an even greater need for the products they sell. It just isn't so.
What is true is that the growing base of Mac users are being increasingly targeted and exploited for scams that seek to defraud them of their hard-earned money. Criminals who seek to do that cannot succeed without your help. Don't give them the satisfaction.
The following describes simple principles that will serve to protect your Mac, and yourself, from the various threats that exist today. It's long, but if you read nothing else, read the first three numbered points and the Summary at the end. They are equally applicable to Macs, PCs, mobile devices or anything else that uses software to communicate with the world beyond it.
There will always be threats to your information security associated with using any Internet - connected communications tool:
macOS already includes everything it needs to protect itself from viruses and malware. Keep it that way with software updates from Apple.
Rather than asking which non-Apple "anti-virus" or "Internet security" product is best, a much better question is "how should I protect my Mac":
Summary: Use common sense and caution when you use your Mac, just like you would in any social context. There is no product, utility, or magic talisman that can protect you from all the evils of mankind.