הלכה אויף דברים 34:1

And it is customary on the last day of the festival - which is called Simchat Torah, because the entire people is happy about the conclusion of the Torah - to have more than a quorum read the Torah: Everyone in the congregation reads, as do people who are not accustomed to go up [to the Torah] and read on other days of the year. And this custom is in order to increase joy. But [only one] individual reads from "And Moshe ascended" (Deuteronomy 34:1) to "And Yehoshua son of Nun" (Deuteronomy 34:9), in [Parashat] Zot HaBerakhah; and [these verses] should not be divided into two. And we have already written the entire order above in the order of the Torah readings.