Parking?

This is probably a question asked many times but I can't seem to find a definite answer when searching for parking. 

If I order parking online today for a show tonight, do I need to pick up the parking ticket at the box office or can I bring my receipt to the lot?  Or is there a list of names at the lot?  Thanks!

In case anyone is interested in the future, you just goto the lot and your name is on a list if your parking isn't mailed to you.  Tickets.com's message was mis-leading, it said the parking ticket would be at the box office.