How to create a Windows 10 USB stick on macOS

The easiest way is to use Windows inside a VM to create the Windows USB stick.

1. Get a Windows 10 ISO image from somewhere.
2. Download VirtualBox and create a virtual machine from the ISO image.
3. Connect the USB stick with the virtual machine.
4. Download rufus and use it to burn the ISO to USB. (Set Partition scheme to MBR)

If you have no Windows 10 ISO image you can use a virtual machine provided by Microsoft. And inside the virtual machine you can use the Windows 10 media creation tool to create a Windows 10 USB stick.