What is the ruling on saying "Allahumma Ameen," and is it incorrect, and the correct form is "Ameen" or "Ameen, O Lord"?

pronunciations: elongated (madd) and shortened (qasr), both with a light mīm. Its meaning is “Answer (our prayer),” and it has also been interpreted as “O Lord, do it,” or as equivalent to saying “O Allah.” This word was established to request divine response and acceptance of supplication. It is permissible to add ‘Allāhumma’ or ‘Yā Rabb’ before or after it outside of prayer, but not during prayer, as its usage there is restricted to the prescribed remembrance. Prophetic traditions indicate the significance of saying Āmīn both within and outside of prayer. The word Āmīn alone conveys the meaning of ‘O Allah, respond,’ and suffices without additional wording.