(11) باب وُجُوبِ قِرَاءَةِ الْفَاتِحَةِ فِي كُلِّ رَكْعَةٍ وَإِنَّهُ إِذَا لَمْ يُحْسِنِ الْفَاتِحَةَ وَلاَ أَمْكَنَهُ تَعَلُّمُهَا قَرَأَ مَا تَيَسَّرَ لَهُ مِنْ غَيْرِهَا
'Ata' reported it on the authority of Abu Huraira who said:
Recitation (of Surat al-Fatiha) in every (rak'ah) of prayer in essential. (The recitation) that we listened to from the Messenger of Allah (ﷺ) we made you listen to it. And that which he recited inwardly to us, we recited it inwardly for you. And he who recites Umm al-Qur'an, it is enough for him (to complete the prayer), and he who adds to it (recites some other verses of the Holy Qur'an along with Surat al-Fatiha), it is preferable for him.
Reference: Sahih Muslim 396 c
In-book reference: Book 4, Hadith 46
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 780