Online payments for an online course. How does it work?

There is no way of knowing for sure. But if someone has a well-designed and fully-featured web-site, it's one sign that they have invested. Crooks don't tend to invest in something they know they'll only have temporary use of.

Secure communication methods and tokenization, payment gateways communicate between your online store/website and your bank. Customer data is collected, validated, approved, and then the payment is accepted, debiting your customer's account.