Is it haram to pay before delivery on online sites? And is it permissible to pay before food is prepared in a restaurant or after eating it?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is permissible, when purchasing through electronic websites, for the buyer to pay via the website and then receive the goods afterward, regardless of whether the purchased item is food or something else, and whether the food is ready at the time of purchase or not. There is no objection to any of this, except in the case of buying gold, silver, or similar items that are subject to the rules of riba (usury). For such items, it is necessary that the exchange (payment and delivery) occurs in the same session; thus, it is not valid to pay for them on the website and then receive them at a later time.

Allah Knows best.