what are the best security systems for Mac

The best antiviruses are MalwareBytes and BitDefender. Though I recommend MalwareBytes. It’s free but there is also a Pro version. I’m pretty sure the pro version is a subscription though. You should turn on FileVault too, for physical protection.

Hope I could help!

An answer depends on what you mean by "security system". Security against theft, damage, unauthorized use...?

Effective defenses against malware and other threats - Apple Community expands on the subject of computing security in general, and Macs in particular.

The above User Tip addresses that concern, but please write back if you need help.