While a virtual machine is running, you can change removable media in the Devices menu of the VM's window. Here you can select in detail what Oracle VM VirtualBox presents to your VM as a CD, DVD, or floppy drive.
The settings are the same as those available for the VM in the Settings window of VirtualBox Manager. But as the Settings window is disabled while the VM is in the Running or Saved state, the Devices menu saves you from having to shut down and restart the VM every time you want to change media.
Using the Devices menu, you can
attach the host drive to the guest or select a floppy or DVD
image, as described in
The Devices menu also includes an option for creating a virtual ISO (VISO) from selected files on the host.