billing zip code means the zip code of the place where the credit card is located, which is generally filled in by Americans.

Credit Card means credit card.

ZIP numbers are often translated into a bar code and printed on envelopes, so that the machine can sort mails more easily. Different from most other barcodes, the postal network uses long and short barcodes, not ordinary thick and thin barcodes. This barcode can be printed on the envelope by any sender (using some word processing software, such as WordPerfect and Microsoft Word).

or, the post office will print it on the envelope when processing the mail. Post offices usually use optical character recognizers to read bar codes, but when necessary, they can distinguish them with naked eyes, because machines sometimes print bar codes on the wrong places of postcards, which makes them smeared.

expanding information

postcode use

postcode is to realize the scheme of letter sorting automation, because the computer can't recognize Chinese, but it can recognize numbers. Code each area, and you can use computer to sort quickly. Of course, the finer you write, the better.

postal code structure

China's postal code adopts a four-level six-digit coding structure. The first two digits represent provinces (municipalities and autonomous regions); The first three digits indicate the postal area; The first four digits represent counties (cities); The last two digits indicate the delivery office (office).

Reference: Baidu Encyclopedia-Postal Code