It actually depends on the location, in my state they give you a code to the actual game, at least that's how Destiny 1 was with all of it's expansions. :)
I owned D1 on disk then purchased the expansion pass online, so never had to deal with it. I found out with RoI (both on the forum here and by contacting Gamestop) that the preorder purchase for it was actually just a money code they give you which gave you currency on the stores so you had to buy it on the console stores (I'm sure you remember all the forum posts about people complaining they preordered only to find out it just popped money on and they couldn't preorder because they waited), so I wanted to call and ask about D2.
For D2, the one here is giving a money code for 59.99, 89.99, and 99.99 [no tax included, which sucks] that just deposits that amount onto your SEN/MS store's currency. It's interesting that it might be different in different locations for the same store or that online might change depending on your region.