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There are not much viruses for Macs like Windows. Macs are virtually invulnerable to viruses out there (there are some adwares out there though). You really don't need any Anti Virus for your Mac. They are just selling the anti virus for money. As long as you don't install any applications from untrusted websites, you will be fine. Virus usually affect the root system files and your Mac will not allow any programs to modify or access the root system files without your permission. To install any applications that access root files, it will ask for user account and password. Don't allow permission to apps that you don't trust, like the apps trying to download automatically from internet.
Also as long as you do regular software updates from Apple, you will be fine as Apple releases security updates frequently.
However, just download and scan using this application on your Mac, AntiMalware application --> https://www.malwarebytes.com/antimalware/mac/
This is to remove unwanted adwares from your Mac if you accidentally installed anything on your Mac.
If you have any questions or would like any additional information, please don't hesitate to ask