It is generally not possible to deposit a check, including a trust fund check, directly onto a Discover credit card. Credit cards are designed for borrowing money and making purchases, not for making deposits or holding funds. If you want to access the funds from your trust fund check, you will need to deposit the check into a bank account and then use the funds from that account to pay your credit card balance or make purchases. Some Discover credit cards offer cash-back rewards, which allow you to earn a percentage of your purchases back in cash or statement credits. However, these rewards are different from actual cash, and you will not be able to use them to make purchases or withdraw money the same way you could with funds in a bank account.