A writ of habeas corpus refers to a court order that is issued to either an agency or a person who is holding someone in custody. In Texas, the state writ of habeas corpus is a legal mechanism that allows individuals to challenge their detention or imprisonment.A writ of habeas corpus is a court order issued either to an agency or a person who is holding someone in custody. An application for a writ of habeas corpus asks a court to overturn your conviction because of a state or federal constitutional violation. A writ of habeas corpus is a legal order that requires the custodian to bring the detained individual before a court or judge. A writ of habeas corpus stands as a vital legal tool, essential for safeguarding individual rights and averting arbitrary detention. Any prisoner, or another person acting on their behalf, may petition the court, or a judge, for a writ of habeas corpus. Writ of habeas corpus even if not raised first in the trial court. App.–San Antonio 1996, pet. App.—San Antonio 1991, pet.