Anas was asked how the Prophet ﷺ used to recite. He replied that his recitation was drawn out with elongation. Then he recited "In the name of Allah, the Most Gracious, the Most Merciful" [Fatihah 1:1], elongating "Bismillah," elongating "ar-Rahman," and elongating "ar-Rahim."
حدثنا عمرو بن عاصم حدثنا همام
سئل أنس كيف كانت قراءة النبي ﷺ فقال كانت مدا ثم قرأ {بسم الله الرحمن الرحيم} يمد ببسم الله ويمد بالرحمن ويمد بالرحيم