In keeping up with tradition, Microsoft has launched Windows 8.1 in both digital and physical form. Users can install the new operating system by using either a downloaded ISO file or the provided DVD. But what happens when neither option is right for you? You can use a USB drive.
url: https://betanews.com/2013/11/06/how-to-create-a-bootable-windows-8-1-usb-drive/