"The Messenger of Allah ﷺ used to pray witr with three rak'ahs. In the first he would recite "Glorify the Name of Your Lord, the Most High;" in the second: "Say: O You disbelievers!" and in the third: "Say: He is Allah, (the) One.'" (Using translation from Nasāʾī 1702)
أَنَّ رَسُولَ اللهِ ﷺ كَانَ يُوتِرُ بِثَلَاثٍ يَقْرَأُ فِي الْأَوَّلِ بِسَبَّحِ اسْمَ رَبِّكَ الْأَعْلَى وَفِي الثَّانِيَةِ بِقُلْ يَا أَيُّهَا الْكَافِرُونَ وَفِي الثَّالِثَةِ بِقُلْ هُوَ اللهُ أَحَدٌ