The zip code is the zip code, used to verify credit card information. Every card in the United States will have a billing address preset by the bank, and the zip code is the zip code of this address. The website's default value range is estimated to be the zip code of the United States, which is only 5 digits. If you enter the wrong zip code, credit card banks in the United States will not allow the money to be deducted, which is why the website requires the zip code. ZIP Code, or Zone Improvement Program Code, is a postal code used by the United States Postal Service (USPS). As you can see, it's a zip code that only applies to US addresses. ZIP Code implies that mail can be delivered to the destination more efficiently and quickly. The most basic ZIP number consists of five numbers, with four numbers later added to allow mail to be delivered more precisely to its destination. The ZIP number after the added number is called "ZIP 4". For example: 22162–1010. The 1st, 2nd, and 3rd digits represent the distribution area or processing and distribution center, the 4th and 5th digits represent the post office or distribution area, the 6th and 7th digits represent the community, and the 8th and 9th digits represent the section. There is another interesting thing: As we all know, credit cards in the United States basically do not have passwords. Therefore, domestic people do not need to enter a password when swiping VISA or MasterCard in the United States. However, if you are traveling by car, you cannot directly swipe your card to refuel at a gas station. , because the machine will ask you to enter the "ZIP Code". At this time, you can go to the gas station store and tell the clerk what gas station number you parked your car at and how much gas you want to fill. The clerk will help you swipe your card and then you can use the refueling gun. This is also to prevent theft. It's a measure.