I thought you could Only buy thru Disney site! I got ours online and it was fast n easy.
They will be physically sent to you but
You will get a confirmation after purchase.
If you have the Disney app, they will also be listed/linked there ( each pass has a number) and you will be able to set ur fastpasses Still following those set of requirements etc...
When u get to the park, you will be asked for Proof for each pass .. Like if for resident etc) and they will Activate for you!
It was easy peasy.
And I love the app as well.
Hope that was clear...