Enabling Clipboard: VirtualBox Manager -> Settings -> General -> Advanced -> Shared Clipboard /Drag’n’Drop: bidirectional
Installing Guests Additions:
Enabling optical drive: VirtualBox Manager -> Settings -> Storage -> Controller Sata -> Adds optical Drive -> Leave Empty
Copy Guest Additions to the available folder on Mac: Finder -> Applications -> VirtualBox right click, Show Package Content -> Contents -> MacOS: copy VBoxGuestAdditions.iso somewhere to the folder
Open disk on virtual machine: Run VM -> top menu, Devices -> Optical Drives -> Choose disk image -> choose the file you’ve just copied
Mount Guest Additions and install: open terminal ->
mkdir temp sudo mount /dev/cdrom temp cd temp chmod u+x VBoxLinuxAdditions.run sudo ./VBoxLinuxAdditions.run reboot
sudo apt update -y && apt upgrade
sudo apt install dkms linux-headers-$(uname -r) build-essential
You must do this before execute ./VBoxLinuxAdditions.run, since the kernel may need update and kernel source should be installed when the scripts compile the vbox modules.