Based on this documentation https://www.linuxlefty.com/posts/enabling-webcam-virtualbox-windows-linux/ dirived originally from the Virtualbox documentation https://www.virtualbox.org/manual/ch08.html
To list the webcams that are installed on the system and available to VirtualBox, use the command:
VBoxManage list webcams
Sample output:
$> VBoxManage list webcams
Video Input Devices: 1
.1 "Laptop_Integrated_Webcam_HD: In"
/dev/video0
Now must link the device /dev/video0 with the target virtual machine (the guest) (my guest is named Windows10)
$> VBoxManage controlvm Windows10 webcam attach /dev/video0
Verify the new configuration:
$> VBoxManage controlvm Windows10 webcam list
/dev/video0