If you are looking to run macOS Catalina in a virtual machine (e.g., VirtualBox or VMware) rather than on bare metal, you may need a pre-created, full installer DMG.
Now that you have a bootable installer, follow these steps to clean install Catalina: If you are looking to run macOS Catalina
Close Disk Utility and select Install macOS from the main menu. Follow the on-screen instructions, selecting your freshly erased drive as the destination. Alternative: Direct DMG Download (For Virtual Machines) you may need a pre-created
Use the official Apple link to download the InstallMacOS.dmg file [3]. If you are looking to run macOS Catalina