sudo apt-get update

sudo apt-get install virtualbox-6.1

https://www.virtualbox.org/manual/ch02.html#install-linux-prereq

https://askubuntu.com/questions/777308/virtualbox-problem-kernel-module-is-not-loaded

sudo apt-get install dkms build-essential linux-headers-`uname -r`

apt-get install --reinstall virtualbox

https://askubuntu.com/questions/777308/virtualbox-problem-kernel-module-is-not-loaded

https://askubuntu.com/questions/760671/could-not-load-vboxdrv-after-upgrade-to-ubuntu-16-04-and-i-want-to-keep-secur/768310#768310