Sophia here from Shopify. Welcome to the Shopify Community!
When you're setting up a store or updating payment settings, you can place a test order to ensure the checkout is functioning as expected.
Have you been experiencing issues with the checkout on your store? If you ran into an error message while testing payments, have received reports from customers, or see any error messages when viewing payment events under Orders > Abandoned checkouts, please let me know and I'd be happy to provide some more information based on specific error messages.