The ruling on one who leaves a pillar of the prayer

If a person says the closing salam of the prayer and then remembers that he forgot a pillar of the prayer, or if he is in doubt, does he perform a rak'ah or does he repeat the prayer?
Answer: If he is certain that he left a pillar, he performs a rak'ah and prostrates for forgetfulness after he says the salam. He prostrates for forgetfulness after the salam. As for if he is in doubt, nothing is required of him. Doubt after the prayer is not considered and has no effect. If he says the salam while believing that his prayer is complete, and then doubts arise after that, there is no blame on him. In fact, these are whispers that he should not pay attention to. However, if he is certain that he left the bowing or the prostration, he performs a rak'ah to complete his prayer, then he prostrates for forgetfulness after the salam. And if he prostrates before the salam, there is nothing wrong with it.
The presenter: May Allah reward you with good.