You can pay for your ticket by card on the seller’s website. Within 3 hours after payment, you’ll get your itinerary receipt (ticket) at the email address you specified in the booking form. If you didn’t receive it, check your Spam folder and make sure there were no mistakes in the email address. What should you do if you didn’t get your ticket?
You don’t have to print out your itinerary receipt. It’s only really there so that you don’t forget your flight details. The airline staff will only require your travel document to find you in the booking system and check you in (if you haven’t already checked in online). They’ll give you your boarding pass, which you’ll need to board the plane.