Tex. Transp. Code § 201.934

The commission may adopt rules regarding the method of payment of a fee for a license issued under this subchapter. The rules may authorize the use of electronic funds transfer or a valid credit card issued by a financial institution chartered by a state or the federal government or by a nationally recognized credit organization approved by the department. The rules may require the payment of a discount or service charge for a credit card payment in addition to the fee.