Bookkeeping day is the day to record consumption. For example, I swiped my card on September 9, but because the merchant didn't ask the card issuer for money in time, I didn't ask for money until the next day. Then the entry date of this transaction is September 10. In most cases, it will be recorded on the trading day.

The bill date is the date when each bill is issued. For example, if the cardholder's bill date is 16, then the credit card withdrawals from 17 August to 16 September belong to the same bill.