You may have different accounts listed in your credit report with different associations attached to you. Under the account list you will find your association to a particular account as individual, cosigner, joint account holder or authorized.
An individual responsibility means that you are the single account holder with the sole responsibility of paying off the debt. Cosigner and joint account means basically the same thing which means that even though you are not the primary account holder you have taken on the responsibility to pay off the debt in full if the primary party is unable to do so. Joint account for is usually referred to counts with a revolving balance such as a credit card whereas a cosigner is generally listed for installment accounts such as mortgage, car loan etc.
An authorized user is simply a person who has been added on but someone who is not liable for any payment on account at all.