I assume you're looking for this on the Import screen. Two thoughts -
1 - Make sure you've chosen one of the first three import modes on the top of the dialog - Copy as DNG, Copy, or Move. There is no Destination panel when you choose Add because you're just adding the images in their current location.
2 - If you have chosen any of first three modes and still don't see the Destination panel, right-click on one of the panel headers that are visible. You'll get a fly-out that let's you choose what panels you want to see. Check the ones you want to see or just click Show All.