If you buy a ticket through the 95583 call center, you can ask the agent to mail a trip to travel itinerary for free at the same time, but this travel itinerary will be sent on the next working day after the flight takes off.
You can also go to the Air China counter at the airport and print it yourself. If you forget it, you can also request to reissue it to travel to travel itinerary through the 95583 call center within one year from the date of issuing the ticket.