How does buying your Disney tickets online work?

I'm a Florida resident. My boyfriend and I want to go to Disney next month for our anniversary. I want to order online. How does this work, though? Do they send you the tickets in the mail or do you pick them up at the park?|||You order them online, then pick them up at the ticket booths at the parks. A driver's license is all you need for proof of residence.|||Be sure to pick them up at a Downtown Disney ticket window to avoid the parking charge.