If you are attempting to install Catalina via a virtual machine or on unsupported hardware, a raw .app installer isn't enough. You need an (an image file of an optical disk) to act as a bootable installer. Why a "New" ISO?
Your bootable file is now sitting on your Desktop, ready for deployment. System Requirements for macOS Catalina macos catalina 10157 iso download new
If you are attempting to install Catalina via a virtual machine or on unsupported hardware, a raw .app installer isn't enough. You need an (an image file of an optical disk) to act as a bootable installer. Why a "New" ISO?
Your bootable file is now sitting on your Desktop, ready for deployment. System Requirements for macOS Catalina