The canonical source for the Quran is not the written book (which is called a https://en.wikipedia.org/wiki/Mus'haf) https://en.wikipedia.org/wiki/Mus'haf). The

The canonical source for the Quran is not the written book (which is called a https://en.wikipedia.org/wiki/Mus'haf) https://en.wikipedia.org/wiki/Mus'haf). The Quran itself has always been transmitted orally and it still is. The memorisation is usually done by people called a https://en.wikipedia.org/wiki/Hafiz_(Quran) https://en.wikipedia.org/wiki/Hafiz_(Quran) and their recitation is treated as the primary source for correctness. The closest thing to a variant would be one of the ten "readings" or https://en.wikipedia.org/wiki/Qira%CA%BCat https://en.wikipedia.org/wiki/Qira%CA%BCat