Apple Pay question about card numbers on online apple pay purchase

[kofman13]

Hi. new to using my credit card with apple pay. I have a question. i have my credit card added to apple pay. say i use apple pay to pay with my credit card online in an app, say Taco Bell, or Grubhub. before i double click side button to confirm, apple pay interface showed what card i am using and the last 4 digits of it, my billing address and phone number and name. i didnt think much of it. but now im paranoid. how much personal info does Apple Pay send to the seller in transactions? name and billing too? i thought the whole point of apple pay was to be a middle man payment processor to add safety privacy and be a go between you and the seller? on a side note, before i checked out with apple pay it showed what card i will use along with the last 4 digits. but later in wallet app, it shows my physical card, but then an "apple pay card number" "use the last four digits to identify apple pay transactions made with this card. this number is unique to this device." so which card if any, did it send to the seller? my real card number or my "apple pay card number?" thank you. new to all this