Apple does not host direct ISO files. Instead, they provide "Install Assistant" packages. To get a genuine file:

: Use hdiutil convert to change the .dmg or .cdr file into a standard .iso format. Compatibility Note

On modern macOS, you can use the command softwareupdate --fetch-full-installer --full-installer-version 10.15.7 to download specific versions directly from Apple's servers.

The demand for legacy operating systems never truly fades. Whether you are a developer testing software compatibility, a system administrator managing a diverse fleet of computers, or a tech enthusiast looking to revive an older machine, the search term remains one of the most popular queries in the Apple ecosystem.

Once you have the ".app" installer file from Apple, you must convert it to an ISO to use it for virtualization (like VirtualBox) or burning to a DVD. Open Terminal on a Mac.

Are you looking to download a Mac OS X ISO file for your 64-bit system? You're not alone. Many users need to create a bootable USB drive or virtual machine with Mac OS X for various purposes, such as:

The final version for many legacy Macs.

Mount the image and use the createinstallmedia tool located inside the app package.

For the virtualization community, a user named "RehabMan" (legacy) and "Geekrar" maintain pre-modified ISOs for VMware. These have VMware Tools pre-injected.

Popular for VMware and VirtualBox setups. Official Ways to Download macOS ISOs