Me, personally. this works for me :
sudo apt-get install virtualbox
If that does not do for you (minimal chances) than the eloborated manual way :
Start by importing the GPG keys of the Oracle VirtualBox repository to your system using the following wget commands:
wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -
wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -
Copy the above commands.
Both commands should output OK which means that the keys are successfully imported and packages from this repository will be considered trusted.
Next, add the VirtualBox repository with the add-apt-repository command as shown below:
sudo add-apt-repository "deb [arch=amd64] http://download.virtualbox.org/virtualbox/debian $(lsb_release -cs) contrib"
If you get an error message saying add-apt-repository command not found then you need to install the software-properties-common package.
Once the VirtualBox repository is enabled, update the apt package list and install the latest version of VirtualBox 6.0 with:
sudo apt update && sudo apt install virtualbox-6.0