Fixing virtual box guest OS resolution

Just installing a Virtual Box application and installing guest Operating systems won’t provide required resolutions.

This is true in case of both Windows OS and Linux OS as guest and Mac OS as host.

The guest OS might not scale to the host resolution and might need scrolling and look like this:

(Visible scroll bars)

It needs installing virtualbox guest additions inside the guest operating systems.

For Debian Linux

For Windows 10

It should be similar for any other guest operating systems if resolution issue exists.