For Muslims, the Holy Book of the Koran is the main book of the believer and the focus of the main thoughts and provisions of Islam. Translated from Arabic, the word "Quran" means "reading aloud" or "edification".
When the Prophet Muhammad was at the age of forty, the first revelation was sent down on him. This happened on the Night of Power, which falls on the month of Ramadan.
Then, for twenty-three years, the transmission of the Holy Book of the Koran was carried out through the angel Jabrail, which, after the words of the Prophet Muhammad ﷺ, was written down by his companions.