Malware

MalwareBytes may not be needed if you describe what you are seeing. The most common problem are Notifications that tell you that you have a virus and can be solved easily by going to Safari > Settings > Websites > Notifications, and Deny websites from sending notifications.

MalwareBytes is effective only when needed, so a description of your problem may be beneficial.

What are you seeing to make you believe you have malware on your Mac?

You download the free trial (14-day) of Malwarebytes for Mac, install and run it, then remove it from its Help menu. If you actually have any malware, the application may or may not report what it finds and removes. Reboot your Mac afterward.

You can avoid malware infestations in the future by only installing software that you directly obtained from the vendor site, or Apple's Mac App Store.