A person under age 18 cannot get a credit card based on his own creditworthiness, states Discover. He can obtain a credit card as an authorized user on a parent's or other relative's account who is 21 or older.
A family member can add a child to an established line of credit and obtain a card printed in the child's name for his use, details Bankrate. Legally, the child under the age of 18 is not responsible for paying back the debt. This is the responsibility of the account holder whose name and credit is attached to the account. Those under 18 can still build a credit history if the card issuer reports positive payments and activity to credit bureaus on the authorized user's behalf.