Sahih al-Bukhari — Call to Prayers (Adhaan) — Hadith No: 772
Translation
Narrated Abu Huraira:The Qur'an is recited in every prayer and in those prayers in which Allah's Messenger (ﷺ) recited aloud for us, we recite aloud in the same prayers for you; and the prayers in which the Prophet (ﷺ) recited quietly, we recite quietly. If you recite "Al-Fatiha" only it is sufficient but if you recite something else in addition, it is better