Tex. R. App. P. 52

As amended through March 28, 2019
Rule 52.1 - Commencement

An original appellate proceeding seeking extraordinary relief - such as a writ of habeas corpus, mandamus, prohibition, injunction, or quo warranto - is commenced by filing a petition with the clerk of the appropriate appellate court. The petition must be captioned "In re [name of relator]."

Tex. R. App. P. 52