UmmSharik Al-Ansari said:
"The Messenger of Allah (ﷺ) commanded usto recite the Opening of the Book (Al-Fatihah) in the funeralprayer." (ID)
English reference (ID): Vol. 1, Book 6, Hadith 1496 (ID)
Arabic reference (ID): Book 6, Hadith 1563 (ID)