California Code, Education Code - EDC § 42634

Each order drawn against the funds of a school district shall be numbered and shall state:  (a) the particular fund or funds of the district against which it is drawn, (b) the amount of the payment to be made from each fund, and (c) the rate of salary and the period of service of any employee of the district for whom an order is issued for payment of salary or wages.

If drawn for any purpose other than the payment of salaries or wages of school district employees, the order shall be accompanied by an itemized bill showing the separate items and the price of each.  Notwithstanding that requirement, if the county superintendent of schools determines that including an itemized bill with the order is impractical under the system of payment utilized, the itemized bill showing the separate items and the price of each shall instead be retained by the school district and shall be available for audit as directed by the county auditor.