Fly by Night and Day
3 Decades of Experience working for United Airlines!
Go to the main page at United.com. Type in your confirmation number under Manage Reservations. You can print your boarding pass 24 hours in advance.
I'll try to make it easy.
You can print a copy of your itinerary anytime from the united.com site under the Reservations tab and drop down into Change/View existing reservations, enter your reservation number and print. You can get your boarding pass within 24 hours of your departure by checking in on line by clicking on the Reservations tab and drop down list to Check in for flight.