Is supplication after the tashahhud a pillar, the omission of which invalidates the prayer, or is the Abrahamic prayer a substitute for it, and is the prayer of one who does not supplicate after the tashahhud invalid? What is the ruling on the supplication "O Allah, I seek refuge in You from the torment of Hellfire," and is it a pillar, the omission of which invalidates the prayer? And what is its correct wording?

Supplicating after the final Tashahhud is recommended according to the majority of scholars, and sunnah according to the Hanafis. Neglecting this supplication does not invalidate the prayer, as it is neither a pillar nor an obligation. The best of the reported supplications are those that came from the Prophet, peace and blessings be upon him, such as seeking refuge from the punishment of Hellfire, the punishment of the grave, the trials of life and death, and the trial of the Antichrist (Al-Masih Ad-Dajjal). As for the Ibrahimi prayer (Salat al-Ibrahimiya), it is a sunnah in itself. Praying upon the Prophet, peace and blessings be upon him, in the final Tashahhud is a pillar according to the Shafi'is and the well-known opinion among the Hanbalis, while it is omitted by the Malikis and Hanafis.