There are two ways you can add someone to your credit card account - as an authorized user on the account or as a joint account holder.
In both cases, the other person on the credit card can make charges to the card. Credit card activity affects the authorized user or the joint account holder the same way it does the primary account holder.
The major difference between the two is the legal obligation to pay the credit card balance.
An authorized user has no legal obligation to pay back the credit card debt. Though late payments will affect the authorized user's credit as long as he's on the account, the credit card issuer can't go after him for payment.
On the other hand, the joint account holder does as much liable for paying back the credit card balance as the primary account holder. The credit card issuer can use all legal methods to go after both people for payment.
In many cases, the joint account holder must meet the credit and income requirements to be added to the account and can be denied if the requirements aren't met. Some credit card issuers might waive these requirements for a fee.
