Some airports like Marrakech don't accept electronic boarding passes so you need to have them printed off before arrival or check in at the airport. If you don't have a smart phone, no problem. Log on to the airline's website, do what you need to do and print off the boarding pass. Stash with your passport and life's good.
One thing I found out, the printed boarding pass for the JFK-LHR leg did not have the terminal printed on it, whereas the app boarding pass did... And no, the 2 different folks checking our BP at the lounges did not twig that we were in the wrong terminal....