ENOfficial
Abu Ayyub reported God’s Messenger as saying, “The witr is a duty for every Muslim, so if anyone wishes to observe it with five rak'as he may do so; if anyone wishes to observe it with three he may do so; and if anyone wishes to observe it with one he may do so.” Abu Dawud, Nasa’i and Ibn Majah transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي أَيُّوبَ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الْوَتْرُ حَقٌّ عَلَى كُلِّ مُسْلِمٍ فَمَنْ أَحَبَّ أَنْ يُوتِرَ بِخَمْسٍ فَلْيَفْعَلْ وَمَنْ أَحَبَّ أَنْ يُوتِرَ بِثَلَاثٍ فَلْيَفْعَلْ وَمَنْ أَحَبَّ أَنْ يُوتِرَ بِوَاحِدَةٍ فَلْيَفْعَلْ» . رَوَاهُ أَبُو دَاوُد وَالنَّسَائِيّ وَابْن مَاجَه
sunnah.com