The IOU states that the credit card borrowed from someone is invalid. You should write down how much money you borrowed today, rather than how much money you borrowed from your credit card. Writing this way does not meet the requirements. It is invalid to write like this. It will be very troublesome to ask for money in the future, and you may not get it back. Credit cards cannot be borrowed from others, as it involves your personal credit score. Failure to repay in time will have serious consequences.