It allows you to pay all or part of its debts over time.
Secured debts are where the creditor has collateral.
That is, it has something that it can repossess if the debt is not paid. Under Chapter 13, you propose a Plan by which you will make monthly payments to a Standing Chapter 13 Trustee. The Trustee will then distribute the funds to the creditors according to the Plan. Under the Plan, you may not have to pay all the creditors in full. Also, the creditors must receive at least as much as they would receive if the you had liquidated in Chapter 7.