In many cases, you can cancel your credit card through your online account management. This is typically the easiest and fastest ways to cancel a credit card, simply because you won’t have to deal with customer service reps whose jobs are to convince you to keep the account open.
First, however, you should make sure you pay your balance and anything you owe in full. If you aren’t able to pay in full, see if you can transfer your balance to another card with a lower APR. Then, whether you cancel online or over the phone, you will want to send written confirmation to make sure the account is canceled. You don’t want to risk thinking the card account is closed only for it to pop up later on. After sending written confirmation, and checking your credit reports to be certain the account is reflected as closed, it’s wise to cut up the card.