Tex. R. Civ. P. 509.3

As amended through August 27, 2024
Rule 509.3 - Citation: Issuance; Appearance Date; Answer
(a)Issuance. When the tenant files a written petition with a justice court, the judge must immediately issue citation directed to the landlord, commanding the landlord to appear before such judge at the time and place named in the citation.
(b)Appearance Date; Answer. The appearance date on the citation must not be less than 10 days nor more than 21 days after the petition is filed. For purposes of this rule, the appearance date on the citation is the trial date. The landlord may, but is not required to, file a written answer on or before the appearance date.

Tex. R. Civ. P. 509.3