Tex. Election Code § 192.031

(a) A political party is entitled to have the names of its nominees for president and vice-president of the United States placed on the ballot in a presidential general election if:

(1) the nominees possess the qualifications for those offices prescribed by federal law;

(2) the party's state chair signs a written certification of:

(A) the names of the party's nominees for president and vice-president; and

(B) the names and residence addresses of presidential elector candidates nominated by the party, in a number equal to the number of presidential electors that federal law allocates to this state;

(3) the party's state chair delivers the written certification to the secretary of state before the later of:

(A) 5 p.m. of the 71st day before presidential election day; or

(B) 5 p.m. of the first business day after the date of final adjournment of the party's national presidential nominating convention; and

(4) the party is:

(A) required or authorized by Subchapter A of Chapter 172 to make its nominations by primary election; or

(B) entitled to have the names of its nominees placed on the general election ballot under Chapter 181.

(b) If the state chair's certification of the party's nominees is delivered by mail, it is considered to be delivered at the time of its receipt by the secretary of state.