Nearly gone are the days of paper tickets. Most airlines are seeking a boarding pass of some sort, that can mean checking in online in advance and printing at home, arranging to pick up at the gate, or by using an automated kiosk at the airport. This can also mean checking in online and selecting any available option for mobile boarding pass or use of an app. There is yet to be an industry standard and more adventurous destinations sometimes do defer to older systems, such as paper! Just to add a bit of confusion. Ideally, you'll have a PNR number and your passport or travel documents to hand and all your details will be ready for your arrival.