Ubuntu add-apt-repository command not found error and solution

Originally published at: https://www.cyberciti.biz/faq/ubuntu-sudo-add-apt-repository-command-not-found-error/

Ian trying to run a command named ‘sudo add-apt-repository ppa:foo/bar’ but getting the following error on screen:
     sudo: add-apt-repository: command not found
How do I fix this problem on Ubuntu Linux 14.04 or 16.04 or 18.04 or 20.4 LTS and Debian Linux server?