If you are under 21 years old and cannot show an independent ability to make the minimum periodic payment on the account, the card issuer cannot approve your application unless someone at least 21 years old who is able to make the minimum periodic payment guarantees, co-signs, or otherwise agrees to be liable on the account. The guarantee may come from anyone at least 21 years old with the financial ability to make the payments, and does not have to come from your parents.
If you have friends under 21 who ask you to help them get a loan, consider that if they do not pay, you would be obligated to do so, and if you do not, it will likely hurt your credit history. If they do not make timely payments, this also may appear on your credit report.
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