If you look at the graphic you attached to the question, you'll see the answer already provided.
At a supermarket, where you've already paid, you get a receipt:
1 a : a writing acknowledging the receiving of goods or money
It's only at a restaurant, for example, when you're given a statement of what you ate and how much you still owe, that you are given a bill or check (or cheque, depending on your country).
Once you've paid the bill, then what you get after that is the receipt—an acknowledgement of having paid and what you paid for.
That's why, on leaving a restaurant, you normally have two pieces of paper: one is the bill (the request for money), and the other is the receipt (the proof of having paid).
In informal conversation, we might ask What was the bill? This just means How much did it come to? If you look at your grocery receipt, you can determine what the bill was before before you paid.
But also in informal conversation, in this context, the wording is blurred. If you handed somebody your grocery receipt as proof of what the bill was, you would not actually be handing them the bill—just indicating what it must have been. However, many people don't make this distinction.
In supermarkets, there is seldom a printed copy of a bill (or check). Instead, you simply see the electronic version on the cash register. Once you've handed over the money, what they print out is the receipt.