Writing an ISO image to a USB drive is useful for many reasons. The biggest for me is the ability to create installation or "Bootable" USB drives that allow for a non OS, blank, computer to boot from an external device. This external booting allows for either diagnostic, setup, or recovery purposes on an other wise unusable computer.
What you will need:
ISO image. In this case we will use Linux Mint.
Erasable USB drive/stick with enough space for above ISO.
Writing program like Linux Mint's built in one called USB Image Writer or Belina Etcher which is available on most platforms.
Time... for the image to write to disk... If you can use a USB 3.x device and connection, imaging will move along much faster.
Connect your target device to your computer.
Launch the imaging application.
Choose you downloaded ISO image.
Choose your target USB device. BE CAREFUL! If any other USB devices are attached make sure you verify your target or DATA LOSS may occur !Â
Click on the Write or Flash button depending on the app you used and wait for it to complete.
NOTE: some applications have a verify feature to confirm proper write operation has occurred. This will take extra time.
Review any completion messages and hopefully everything completed for you. Your new bootable USB drive is ready for use.