Since Apple provides a .app installer, you must manually convert it to an ISO using the if you need it for a virtual machine: How to download and install macOS - Apple Support
in your Applications folder, you must manually convert it to an ISO using Terminal commands: Create a blank disk image: Macos Mojave 10.14 4 Iso Download
The most reliable way to get the necessary files is through official channels to ensure system stability and security. Since Apple provides a
Improved Security: Enhanced data protection and camera/mic privacy controls. Since Apple provides a .app installer