ISO files provide a complete image of a CD or DVD for use in a variety of programs. CD and DVD authoring programs make the most frequent use of ISO images, but an ISO image is also useful in virtual machines. Mounting an ISO image in a VirtualBox VM provides the same experience as inserting a physical CD or DVD in any computer, and gives you the ability to access the files on the image and install programs using any installers contained in the CD.
Launch the VirtualBox program. Click the virtual machine you want to work with in the left side of the window. Click the "Settings" button at the top of the window.
Click the "Storage" icon at the top of the Settings window. Click the CD icon in the "Storage Tree" list. Click the CD icon in the "Attributes" section on the left side of the window. The icon is located next to the CD/DVD Drive drop-down menu.
Click the "Choose a virtual CD/DVD disk file" item in the menu that appears. Navigate to the ISO image in the window that appears. Click "Open" after clicking on the ISO file. Click "OK" to close the Settings window and apply the changes. If the virtual machine is running, the CD/DVD ISO image appears immediately in the default CD/DVD drive. Otherwise, the ISO image is available the next time you start the virtual machine.