If I understand the OPC question correctly it is how does one prove that you have a drink package. At boarding day, you should see the correct code on your boarding pass which you can view on the app. When you get on the ship, the code will be on your SeaPass card. Look for CALL or PALL, classic and premium.
If you do not have the code on your card, go to guest relations and they will either print you a new card or they will apply a sticker to your card showing your beverage package.
At that point, all you need to do is show the card to a server. At that point, all you need to do is show the card to a server. Or give the server your room number. They can access the information and they will know which package you have even without showing the card.