Before you can create an ISO, you must obtain the full installer from Apple. All modern versions of macOS (Catalina and later) are strictly 64-bit.
Once the installer (e.g., "Install macOS Sequoia.app") is in your folder, use these Terminal commands to create an ISO: Create a bootable installer for macOS - Apple Support Mac Os Download Iso 64 Bit
This method is complex and often fails. The resulting ISO may not be bootable because Windows cannot properly create HFS+/APFS file systems. A virtual machine (macOS in VMware on Windows) is a better approach. Before you can create an ISO, you must
This guide assumes you are creating an ISO for legitimate use on Apple hardware or a virtual machine on a Mac (which is allowed). Before you can create an ISO
Example using gibMacOS on Windows: