anything and everything related to your Mac, from the basic setup to the advance user its all here at macuser
The scenario is a machine has had its hard drive replaced with a windows Operating System. On the boot menu you don’t get the option to boot to a USB or the recovery software from the Internet option.
Here is a comprehensive list of Apple Hardware that works with which Mac Operating System release. Please remember macOS is not backward compatible so a machine made later than an Operating System wont boot. From Catalina 10.15 the Operating System architecture changed to macOS (64 bit) Mojave and below is running on 32 bit.
macOS Tahoe Mac Hardware