To use Delta Air Lines web check-in online, passengers can visit the airline's website, select the "Check-In" option, and enter their booking reference or e-ticket number. Once the booking is located, passengers can select their seats, and add any additional services such as baggage or meals. Passengers can also check-in and print their boarding pass or have it on their mobile device. Web check-in typically opens 24 hours before the scheduled departure time of the flight and closes 45 minutes before the flight. more info-https://www.airlinesmap.com/de....lta-airlines-web-che