As a course creator, I would like to have the option for my clients to pay by invoice more obvious.

The only two payment options that my potential clients see is credit card and Paypal. Unless I specifically send them the links to jotform, they cannot find out how to pay by invoice.

This is confusing. There was an organisation that paid for 12 students individually, 12 times separately, by credit card. 

Please include the invoice option (= links to the jotform) on the payment page: