Technically, Apple does not release official "ISO" files. Instead, they provide macOS through the Mac App Store as a .app installer or as a .pkg file from their servers.
In the context of Hackintoshing, an ISO (or more commonly a "distro") is a modified disk image of macOS.
: Run the application and select your USB drive from the left-hand sidebar.
Choose compatible hardware. Popular resources include the Hackintosh community forums and Wiki guides.