CNF in IRCTC stands for "Confirmed". It means that the passenger has a confirmed seat or berth on the train. When a passenger books a ticket, their reservation status may show as "CNF" if their booking has been confirmed and they have been assigned a seat or berth on the train. Once the chart is prepared, the CNF status on the train will change with the exact seat/berth number. This is because most tickets are cancelled at this time and IRCTC allots these berths to passengers with CNF tickets. Passengers can check their seat number with the PNR Status feature on the ixigo trains app.