The VirtualBox Guest Additions are designed to be installed inside a virtual machine, after the guest operating system has been installed, and they include drivers and optimizations for better system performance and usability. By installing the VirtualBox Guest Additions, the virtual machine should have better video support (including hardware-accelerated graphics), shared clipboard, drag and drop support between the guest and host machines, and shared folders, among others. This article explains installing the VirtualBox Guest Additions ISO using the built-in VirtualBox installer, for Ubuntu, Linux Mint, Debian or Fedora guest virtual machines, which enables all the available guest additions features.