Email Notification to Store Owner When Order Complete During early development I had it working so the store owner would get an email when an order was completed. I just realized this isn't working anymore. Where are the settings related to this? Is it supposed to use the store's email, or something else?
You didn't mention the versions so I assume you are using Drupal 8 with Commerce 2.
You can use Commerce Reaction module as it allows you to select the Commerce event and have a reaction when it is dispatched.
It provides a plugin to send HTML, and twig template emails with nice integration with the Token module.