Buying on the course page
Every course that is sold online has its own public web page, published by the organisation running it. Choosing Buy this programme on that page takes you to a secure checkout run by Stripe, a payment provider used by millions of businesses. You enter your email address and card details there, and Stripe confirms the payment.
As soon as you have paid, you land on a "Payment received" page confirming your place, with the steps to get started. The same steps arrive by email, so there is nothing to memorise.
The email address you enter at checkout matters. It is where your confirmation is sent, and it is how the app can recognise you later. If you already use the app, enter the same email address your app account uses.