To have a better experience when using Kali-Linux on VirtualBox, you need to install virtualbox-guest-addition. In the new version, the Kali Linux team has made it simple by just using a single command-line. Watch this video for more information!
1- To install VirtualBox Guest Addition, enter the following command in the terminal:
sudo apt install virtualbox-guest-x11{codeBox}
2- Reboot your system to apply the changes.
3- Enjoy ethical hacking!