The state law that sets forth how long a creditor or collection agency can attempt to collect a debt from a person after they default on their payment obligations. The length of time varies from state to state and typically falls somewhere between 3 - 10 years from the date of default. Note that the time can reset/restart whenever a payment is made.
The Statute of Limitations can be used as a defense against a debt collection law suit.
It does not impact how debt is reported on your credit report.