macOS is an Operating System that runs only on hardware developed by Apple Computer from California. Latest versions are available as a free download from the App Store, it requires an Apple ID and an Apple device to download the macOS installer.
Most Linux distros are available to download on the main page of the bistro wanted, Debian shows a link on its front page for direct http download, there are other ways to download it like as a torrent and also there are mirrors to closer locations for faster downloads.
www.debian.org
www.ubuntu.com
www.suse.com
www.redhat.com
www.fedoraproject.org
Latest versions of the Window OS are also available as a free download, the webpage www.microsoft.com/download offers the company’s software available, it can redownloaded as an ISO format file on Mac or Linux, downloading from a Windows OS computer will install a tool called MCT or Media Creation Tool that will get the iso and options to create a bootable media.
