What scripts to use to test the payment form?

Question

Software testing

Hello! Please tell a novice tester for which scenarios it is necessary to test the payment web form? The teacher set the task to test the form for entering card data when paying for a product or service on any site.
There should be checklists and several test cases, there should be about 8 of them, as the teacher told me. Recalling the theory, I suggested that by itself there should be a test for a negative scenario, positive and boundary conditions, if I reason correctly. Please suggest what else needs to be added, what script to check. What are the nuances in this case?