MacOS – How to run a application in Automator

You can simply pass the selected folder to the shell script by selecting "as argument" from the "pass input:" dropdown-menu and then adding "$@" at the point in your script where you want the folder path to be used.

To use drag&drop, just remove the "ask for finder items" action and let the "run shell script" receive the input from "application can receive files and folders as input".

You could always convert your workflows to Automator Applications if you want to be able to run them by double clicking. Open the workflow up in Automator, duplicate it, and save it with a File Format of Application, rather than the default Workflow: