Linux Babe published a tutorial about setting up Amavis and ClamAV on CentOS 8 or RHEL 8 Mail Server.

Setting Up Amavis and ClamAV on CentOS 8/RHEL 8 Mail Server

This tutorial shows you how to use Amavis and ClamAV to scan viruses in email messages. Amavis (A Mail Virus Scanner) is a high-performance interface between a message transfer agent (MTA) such as Postfix and content filters.

Setting Up Amavis and ClamAV on CentOS 8/RHEL 8 Mail Server