Hi, Catherine! I am assuming you are dropping off teenagers at the Magic Kingdom which we did on our last vacation at WDW.  When you pull up to the parking entrance at the Magic Kingdom, simply tell the Cast Member what you are doing, and they will direct you to Guest Drop Off/Pick Up.  It is near the taxi stand at the Ticket and Transportation Center, and you have to keep a keen eye when you return to pick them up since the sign is kind of small.  Once they exit your car, the kids will need to proceed to the monorails which will take them to the Magic Kingdom.  Remember to tell them that once their day is done, they will keep right after they exit the TTC to find the Guest Drop Off/Pick Up area. (Tell them to look for the taxi's if they forget!) Of course, make sure they have a fully charged cell phone before they leave you! Have a wonderful day and a seamless drop off and pick up at the Magic Kingdom!