If wanting to make a virtual webcan, it can be done the next way:

list cameras

ls -l /dev/video*

Install package v4l2loopback-dkms

sudo apt-get install v4l2loopback-dkms

Probe the virtual webcam like /dev/video2

sudo modprobe v4l2loopback video_nr=2 card_label=“Virtual cam”

list cameras and the camera should be seen like

xxxxxxx@xxxxxx-AOHAPPY:~$ ls -l /dev/video*
crw-rw----+ 1 root video 81, 0 huhti 7 13:57 /dev/video0
crw-rw----+ 1 root video 81, 1 huhti 7 17:28 /dev/video2