✔ 最佳答案
ZIP code is the system of postal codes used by the United States Postal Service (USPS). The letters ZIP, an acronym for Zone Improvement Plan.
ZIP code only exist in Uinted States. The rest of the world use postal code.
Hong Kong does not even use a postal code system, not to mention ZIP.
For web form, if they accept non-US address, you can leave it blank, if allow, or use NA, Not Applicable/ Not Available. If something is to be shipped to you by mail, leave it blank is best as it won't confuse the postal system.
If the form insist on numeric ZIP code, they are only accepting US address.