Applecare+ purchase at Costco

I bought my IPad Pro at Costco. At the register I paid for the IPad and Applecare+ at the same time. At the pick up window, I only got the ipad. Nothing on the Applecare+. Was I supposed to get something from Costco on the Applecare+? Was I supposed to get an ipad box that includes both the ipad and Applecare+? If not, how am I supposed to register the Costco Applecare+ purchase with Apple? (The Costco concierge hotline didn't help and I haven't found an answer on Apple's support website.) I feel I'm missing something but no one can tell me what it is.