Do I need to pay in advance when I order in the hotel?

Generally, final settlement is required.

Most hotels just scan the code to pay for things.

When booking a hotel, you can see one of the two, that is, you can pay at the hotel, that is, you need to use a credit card as a guarantee, so you can pay there. If you have it, just pay over there and live in it directly. Either way will do. Choose according to your own choice and do what you think is appropriate.