Tex. Transportation Code § 502.1747

(a) When a person registers or renews the registration of a motor vehicle under this chapter, the person may contribute $5 or more to the Parks and Wildlife Department.

(b) The department shall:

(1) include space on each motor vehicle registration renewal notice, on the page that states the total fee for registration renewal, that allows a person renewing a registration to indicate the amount that the person is voluntarily contributing to the state parks account;

(2) provide an opportunity to contribute to the state parks account similar to the opportunity described by Subsection (a) and in the manner described by Subdivision (1) in any registration renewal system that succeeds the system in place on September 1, 2011; and

(3) provide an opportunity for a person to contribute to the state parks account during the registration renewal process on the department's Internet website.

(c) If a person makes a contribution under this section and does not pay the full amount of a registration fee, the county assessor-collector may credit all or a portion of the contribution to the person's registration fee.

(d) The county assessor-collector shall send any contribution made under this section to the comptroller for deposit to the credit of the state parks account under Section 11.035, Parks and Wildlife Code. Money received by the Parks and Wildlife Department under this section may be used only for the operation and maintenance of state parks, historic sites, or natural areas under the jurisdiction of the Parks and Wildlife Department.

(e) The department shall consult with the Parks and Wildlife Department in performing the department's duties under this section.