Default camera app named cheese may not work on your Ubuntu version even on 18 or 20. But there is another best camera app name Guvcview.
About the App
Guvcview is a best for live camera preview, capture images and record videos. Also free to use.
Open Terminal (Alt+Ctrl+T).
sudo apt-get install guvcview
Press Enter Key, Type your user password.
Using the App
On app search, search for guvcview, and open the application.
There you can directly capture images, record videos, etc.
Recorded videos and images will be saved on your ‘Home‘ location as default.