After that, you can follow one of the three options: mount, burn or create a USB drive. Why is it used?īasically, all the big companies like Microsoft now distribute software like Windows 8 or 10.1 in an ISO file format. That means gone are the times where you need to carry CDs to install the software. Based on ISO-9660, it can copy the exact contents found in a disc such as CD or DVD. An ISO file format is the most common format for disc images.