Does the Macs come with pre installed antivirus

The name of the MacOS anti-Virus is X-Protect. It does come pre-Installed, and gets automatic updates if you allow it to.

It does NOT make a Big Show of reading all your files, and everything coming and going to the Internet, looking for antique Windows viruses that are not a threat to your Mac. That is an extremely stupid way of doing Virus protection, and is what you get if you add most aftermarket so-called Anti-Virus programs.

Aftermarket anti-Virus packages slow down your Mac and make it unstable. Do not install them. If your school or employer insists that you must have one, use ClamXAV, and set to to scan-on-demand ONLY.

No and it doesn't need to since macOS has

read here: macOS - Security - Apple

Do not install any third party anti virus apps. They do no good and may cause problems such as using system resources for no benefit or purpose.

You're welcome.

FYI, I am using the Mac without AV since 2009.