It is possible to use a credit card number without a physical card. This is called card-not-present fraud and can happen in several ways. For example, if a fraudster has your credit card number and expiration date, they may be able to make online purchases or buy something over the phone.
This type of card fraud is harder to prevent because some merchants don’t require a physical card or signature for the transaction. According to credit card fraud stats, CNP fraud cases led to $537.3 million in losses in 2015.