For both organization and individual Workflows, you can set notifications to go to all organization Admin users, no users, or a custom list of users.
Note that these settings are for notification emails when a submission is completed. Anyone who completes a Workflow will still separately have the ability to download their documents, receive emails requesting signatures, and receive emails that signed documents are available for download.
How to change organization default Workflow notifications:
How to change individual Workflow notifications (will override organization defaults):
How to navigate to the Workflow dashboard