From Sahih Bukhari (Hadith 1257):
Narrated Um 'Atiyya:The daughter of the Prophet (ﷺ) expired, and he said to us, "Wash her three or five times, or more if you see it necessary, and when you finish, notify me." So, (when we finished) we informed him and he unfastened his waist-sheet and told us to shroud her in it
Reference: Bukhari 1257