Expedia will only send you a booking corfmniation email, you can choose to print it out or not, that will not be required when you check in either online or at the airport. Your ticket comes in the form of an e-ticket, electronically stored in the airline's computer system. No paper ticket will be issued unless you ask for one which will cost you maybe $10. With an e-ticket you can check in online from the airline's website 24 hours before departure and print out your own boarding pass from home. You can also choose to check in at the airport shortly before the departure time. All you need at the airport is your government issued photo id, make sure the name on your id matches the one on your e-ticket and corfmniation email.