Cal. Civ. Proc. Code § 116.222

If the action is to enforce the payment of a debt, the statement of calculation of liability shall separately state the original debt, each payment credited to the debt, each fee and charge added to the debt, each payment credited against those fees and charges, all other debits or charges to the account, and an explanation of the nature of those fees, charges, debits, and all other credits to the debt, by source and amount.