Once you finished the booking process on a carrier’s website or with an OTA, you will usually receive a code. This combination of letter and/or numbers is your confirmation that you’ve paid for a specific itinerary. This unique identifier is six digits long and will tie you to your booking.
You’ll need this code if you want to view or change your booking. Usually, airlines and carriers will wish to so see your booking code and last name before showing you any more details.
Also, checking in online for your flight can require you entering your booking code.
The booking code is part of the so-called Passenger Name Record (PNR). That’s where all the information about you can your ticket is stored.