This command comes under software-properties-common debian package. Which is not available under the minimal Ubuntu installation, but this package can be installed from default system repositories. If you found apt-add-repository command not found error on your system, Follow this article to add this command to your system.
On Latest Ubuntu & Debian Version’s
The latest version of Ubuntu 20.10, 20.04, 18.04, 16.04 and Debian 10/9/8, apt-add-repository command utility is available under the software-properties-common package. Open a terminal and execute following command: That’s it. You can now use apt-add-repository command to add PPA’s.
Ubuntu 13.10/Debian 7 and Older Versions
The systems running with older versions like Ubuntu 13.10 or Debian 7 (Wheezy) or its earlier versions, Needed to install python-software-properties package to add apt-add-repository command.
Conclusion
This tutorial explained you to how to resolved the issue apt-add-repository command not found on your system.