A dummy ticket seems to be a regular airline ticket and contains a real PNR, booking code, or booking reference number. You can check them there if you choose the "Manage my booking" option or the "My trips" area, both of which are available on many airline websites. Another word for a dummy ticket is an itinerary or airline reservation.
To obtain a complimentary dummy ticket, go to https://www.airdummyticket.com/