The Basic API Access identity provider type allows for basic authentication with conventional username and password.
Basic API Access only allows access to the API and should only be used when the length of an API Key is too long for the provider to accept. User created with this provider type is not authorized to log into the frontend.
The home tenant configured during the user creation is the only tenant the user will have access to.
Once the identity provider is created, to edit, click on the id field. This will open up a form to configure the settings.
More information on creating an enterprise user can be found here: