Tex. Local Government Code § 113.901

(a) Except as provided by Subsection (c), a county auditor may not audit or approve an account for the purchase of supplies or materials for the use of the county or of a county officer unless a requisition, signed by the officer ordering the supplies or materials and approved by the county judge, is attached to the account. The requisition requirement is in addition to any other requirements of law.

(b) The requisition must be made, signed, and approved in triplicate. The original must be delivered to the person from whom the purchase is to be made before the purchase is made. The duplicate copy must be filed with the county auditor. The triplicate copy must remain with the officer requesting the purchase. This subsection does not apply to a county that operates an electronic requisition system.

(c) The commissioners court of a county that has the office of county auditor may, by a written order, waive the requirement of the county judge's approval of requisitions. The order must be recorded in the minutes of the commissioners court. If the approval of the county judge is waived, all claims must be approved by the commissioners court in open court.

(d) The commissioners court of a county may establish an electronic requisition system to perform the functions required by Subsection (a). The county auditor, subject to the approval of the commissioners court, shall establish procedures for administering the system.

(e) An electronic requisition system established under this section must be able to electronically transmit data to and receive data from the county's financial system in a manner that meets professional, regulatory, and statutory requirements and standards, including those related to purchasing, auditing, and accounting.