Setup Virtualbox 6+ shared folder in Kali Linux 2017/2018/2019+

In your kali linux, run

apt -y install virtualbox-guest-x11

reboot

On your host, setup something like this

You should now see your shared directory in /media

ls -la /media

If its doesnt work, also run the following.

On your Kali menu bar,

Devices > Insert Guest Addition CD Image

cd /media/cdroom
cp ./VBoxLinuxAdditions.run ~/Desktop
cd ~/Desktop
./VBoxLinuxAdditions.run
reboot