While an e-ticket serves only as a confirmation of your booked flight(s), a boarding pass documents that you have been checked in and are cleared to board the aircraft.
Visit your airline's website to find out how you can check in for your flight. The carrier's online resources include a lot of other useful information too. We encourage you to review it at the time of booking as well as on the days leading up to your flight. It will help you get everything ready. (Note: When online check-in is unavailable, please remember to bring your e-ticket to the airline service counter at the airport so a boarding pass may be issued to you.)
Furthermore, we strongly recommend reviewing and confirm your itinerary with the carrier 72 hours before scheduled takeoff to make sure you are aware of any last-minute changes.