Nanjing Wei Gang milk, do I have to pay before ordering milk? I can't understand this rule.

Not necessarily. It depends on the milkman. Generally, your campus has a fixed milkman who is responsible for ordering and delivering milk. If you ask him to order the milk directly, or he contacts you directly, you can usually deliver the milk first and settle the bill together at the end of the month. However, this situation is generally limited to ordering milk for the first time, or I didn't find it when I asked you for money at the end of the month. If you order milk, the other party can deliver the milk first and then collect the money. You have to report the plan before you can get the milk and then deliver it.