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On a side note, the -m option indicates that Python is to run the module as a stand-alone script, that is, its contents will be ran within the __main__ namespace. Doing this means you don't have to know the full path to the module, as Python will look for the script in sys.path. In other words, for modules that you would normally import into another Python file can be run directly from the command line.

In the example of running pipenv, the command takes advantage of the fact that Python allows the -m option to run a module directly or allow it to be imported; in this case, pipenv imports venv to create the virtual environment as part of the creation process.