A user is a user of your app who will access flows with other apps using the Integry widget embedded within your app.
You will pass Integry their user ID when you embed the widget so Integry can associate their connected accounts and integrations with them. That same user ID is how you will then identify them in the Users tab.
You can also configure Integry such that the user is an account or a business in your app. Whichever entity you treat as a user, it will be able to view, edit and create all integrations created.