Summarizing the other posts, this is the rule of thumb: for each PC or virtual machine, you require its corresponding Windows license. A virtual machine counts as another machine, i.e. a PC. In addition, go for Windows 10 Pro, not Windows 10 Home. Furthermore, although it depends on your needs, I would recommend for a Mac using the built-in virtualization tool BootCamp. Built-in tools are usually the best choice, and they are free. See for example Hyper-V in Windows which is a great built-in tool. Of course VMWare and other commercial software may be more sophisticated, but then, again, it depends on whether you are a 'power user' or not. Finally, regarding your Windows product license you can transfer it to another computer or virtual machine, but you have to contact Microsoft directly.
Summarizing the other posts, this is the rule of thumb: for each PC or virtual machine, you require its corresponding Windows license. A virtual machine counts as another machine, i.e. a PC. In addition, go for Windows 10 Pro, not Windows 10 Home. Furthermore, although it depends on your needs, I would recommend for a Mac using the built-in virtualization tool BootCamp. Built-in tools are usually the best choice, and they are free. See for example Hyper-V in Windows which is a great built-in tool. Of course VMWare and other commercial software may be more sophisticated, but then, again, it depends on whether you are a 'power user' or not. Finally, regarding your Windows product license you can transfer it to another computer or virtual machine, but you have to contact Microsoft directly.