California Code, Family Code - FAM § 5104

(a) The application for a writ of execution shall be accompanied by an affidavit stating the total amount due and unpaid that is authorized to be enforced pursuant to Sections 5100 to 5103, inclusive, on the date of the application.

(b) If interest on the overdue installments is sought, the affidavit shall state the total amount of the interest and the amount of each due and unpaid installment and the date it became due.

(c) The affidavit shall be filed in the action and a copy shall be attached to the writ of execution delivered to the levying officer. The levying officer shall serve the copy of the affidavit on the judgment debtor when the writ of execution is first served on the judgment debtor pursuant to a levy under the writ.