With the resumption of production quite fresh, cause of the coronavirus pandemic, Apple sets limits for the purchase of devices each customer. In fact, it’s not possible to buy cartons for iPhone, iPad, MacBook Air and Mac mini.
This restriction affects China, France and the United States as well as several parts of the world. Presumably stocks are not in large numbers, and most importantly, Apple certainly prefers as many customers as possible to take advantage of the new features.
As an example, the new iPad Pro 2020 cannot be ordered by two examples, for each screen size (11 ″ and 12.9 ″). For MacBook Air and Mac mini, Apple sets the limit of 5 units for each.
If you had the idea of buying more products than the limit requires, to offer them for example, know that you will need to use several Apple accounts.