This is a supplication of high eminence, and is reported to have been brought by the Angel Jibraeel for the Noble Prophet, peace be upon him and his family, when he was engrossed in prayers at the Maqam-e-Ibrahim. Shaykh al-Kafa'ami has reported this supplication in his book Baladul Ameen and in al-Misbah. It is mentioned that the reward for the one who recites it during the nights of the full moon (13th, 14th & 15th) in the Month of Ramadan is that their sins are forgiven even if they are in such plenty as the drops of rain water, leaves of trees or sand of a desert. It is also very effective for the cure of the sick, fulfillment of debts, acquisition of wealth and relief from sorrows.

Arabic, English with transliteration: https://www.duas.org/mujir.htm

PDF: https://www.duas.org/pdfs/Mojeer.pdf