Which link the external users can log into to see bill management portal?

Summary:

We have completed the setups for external users registration. We can see that now as a user and a role 'Customer Accounts Payable Specialist' is assigned to the user.

1) - when does this user get the email with log in details?

2) - which link does the user have to log in to see bill management portal directly and not anything else?

Content (required):

We have completed the setups for external users registration. We can see that user now as a user and a role 'Customer Accounts Payable Specialist' is assigned to the user.

1) - when does this user get the email with log in details?