Antivirus software is not necessary for most desktop computer users in Zorin OS because of the advanced security features of Linux and the inherently more secure development model of Open Source software.
In order to stay safe from security threats, we would always recommend you to install the latest updates from the Software Updater. This will make sure that you have the latest security patches to avoid any known vulnerabilities.
However, to scan if your computer has malware for other platforms like Windows, you can install a malware scanner called ClamTk from the Software store in Zorin OS (open the Zorin menu > Software > search & install “ClamTk”).
If you want to be more certain that you can’t run any Linux-affecting and cross-platform malware, there are some tools like ESET NOD32 for example.