Texas Code of Criminal Procedure - CRIM P Art. 11.14. Application Requirements

1. That the applicant is illegally restrained in the applicant's liberty, and by whom, naming both parties, if their names are known, or if unknown, designating and describing them;

2. When the applicant is confined or restrained by virtue of any writ, order or process, or under color of either, a copy shall be annexed to the application, or it shall be stated that a copy cannot be obtained;

3. When the confinement or restraint is not by virtue of any writ, order or process, the application may state only that the applicant is illegally confined or restrained in the applicant's liberty;

4. There must be a prayer in the application for the writ of habeas corpus; and

5. Oath must be made that the allegations of the application are true, according to the belief of the applicant or petitioner.