Many shop customers always pay attention to the meaning of a series of numbers after placing an order.

The store with many verification codes refers to the store in Pinduoduo. If many stores invite new users, that string of numbers is the invitation code. If the customer writes down this string of numbers after placing an order, he will fill in the invitation code of the store. If the customer fills in this string of numbers, it means that the new user has been invited successfully, which is a verification of his invitation code. So inviting new users is a string of numbers, which is the verification code.