There are two different types of customer stars:
Hollow star: Portal user
Full star: Customer with payment information (whether portal user or not)
Hollow stars show customers who have either signed up for a test using the portal or using an invitation to the portal that you sent them.
Full stars show customers who have credit card information on file and will be automatically charged for their backflow tests when they are approved from the Review Completed Tests page, if you have Stripe Connect set up. See our article about Setting Up Stripe Connect to learn more.