A client wanted to install some new Multi-factor Authentication software on the background while users where working. After brewing a great cup of Catuai coffee at home I found how to install a .pkg using the Terminal macOS.
This is a simple command. Open your Terminal and ssh to the desired macOS you need to install the .pkg. Run the following command:
sudo installer -pkg /path/to/package.pkg -target /
I usually run the above installer command from the location the .pkg lives. Enter your admin password and it should install without an issue. You should see an output as below: