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". And he would say the Qunut before bowing, and when he finished he would say: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times, elongating the words the last time.  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يُوتِرُ بِثَلاَثِ رَكَعَاتٍ كَانَ يَقْرَأُ فِي الأُولَى بِ { سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى } وَفِي الثَّانِيَةِ بِ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } وَفِي الثَّالِثَةِ بِ { قُلْ هُوَ اللَّهُ أَحَدٌ } وَيَقْنُتُ قَبْلَ الرُّكُوعِ فَإِذَا فَرَغَ قَالَ عِنْدَ فَرَاغِهِ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ ثَلاَثَ مَرَّاتٍ يُطِيلُ فِي آخِرِهِنَّ  

"In the first rak'ah of witr, the Messenger of Allah ﷺ used to 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."  

كَانَ رَسُولُ اللَّهِ ﷺ يَقْرَأُ فِي الرَّكْعَةِ الأُولَى مِنَ الْوَتْرِ بِ { سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى } وَفِي الثَّانِيَةِ بِ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } وَفِي الثَّالِثَةِ بِ { قُلْ هُوَ اللَّهُ أَحَدٌ }  

"The Messenger of Allah ﷺ used to recite: "Glorify the Name of Your Lord, the Most High;" in witr, in the second rak'ah he would recite: "Say: O you disbelievers!"; and in the third "Say: He is Allah, (the) One". And he only said the taslim at the end, and he would say- meaning after the taslim: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy)' three times."  

كَانَ رَسُولُ اللَّهِ ﷺ يَقْرَأُ فِي الْوَتْرِ بِ { سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى } وَفِي الرَّكْعَةِ الثَّانِيَةِ بِ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } وَفِي الثَّالِثَةِ بِ { قُلْ هُوَ اللَّهُ أَحَدٌ } وَلاَ يُسَلِّمُ إِلاَّ فِي آخِرِهِنَّ وَيَقُولُ يَعْنِي بَعْدَ التَّسْلِيمِ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ ثَلاَثًا  

"The Messenger of Allah ﷺ used to recite in witr: Glorify the Name of your Lord, the Most High;" and "Say: O you disbelievers!;' and 'Say: He is Allah, (the) One.' And when he said the taslim, he would say: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times, elongating his words the third time."  

كَانَ رَسُولُ اللَّهِ ﷺ يُوتِرُ بِ { سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى } وَ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } وَ { قُلْ هُوَ اللَّهُ أَحَدٌ } وَكَانَ إِذَا سَلَّمَ وَفَرَغَ قَالَ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ ثَلاَثًا طَوَّلَ فِي الثَّالِثَةِ وَرَوَاهُ عَبْدُ الْمَلِكِ بْنُ أَبِي سُلَيْمَانَ عَنْ زُبَيْدٍ وَلَمْ يَذْكُرْ ذَرًّا  

His father said: "The Messenger of Allah ﷺ used to recite in witr: Glorify the Name of Your Lord, the Most High;' and "Say: O you disbelievers!'; and 'Say: He is Allah, (the) One." And after he had said the salam, he would say: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times, raising his voice with it."  

كَانَ رَسُولُ اللَّهِ ﷺ يُوتِرُ بِ { سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى } وَ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } وَ { قُلْ هُوَ اللَّهُ أَحَدٌ } وَيَقُولُ بَعْدَ مَا يُسَلِّمُ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ ثَلاَثَ مَرَّاتٍ يَرْفَعُ بِهَا صَوْتَهُ خَالَفَهُمَا أَبُو نُعَيْمٍ فَرَوَاهُ عَنْ سُفْيَانَ عَنْ زُبَيْدٍ عَنْ ذَرٍّ عَنْ سَعِيدٍ  

"The Messenger of Allah ﷺ used to recite: "Glorify the Name of Your Lord, the Most High;" in witr, in the second rak'ah he would recite: "Say: O you disbelievers!"; and in the third "Say: He is Allah, (the) One". And he only said the taslim at the end, and he would say- meaning after the taslim: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy)' three times." (Using translation from Nasāʾī 1701)   

كَانَ رَسُولُ اللهِ ﷺ يُقْرَأُ فِي الْوِتْرِ فِي الرَّكْعَةِ الْأُولَى بِسَبِّحِ اسْمَ رَبِّكَ الْأَعْلَى وَفِي الرَّكْعَةِ الثَّانِيَةِ بِقُلْ يَا أَيُّهَا الْكَافِرُونَ وَفِي الرَّكْعَةِ الثَّالِثَةِ بِقُلْ هُوَ اللهُ أَحَدٌ وَلَا يُسَلِّمُ إِلَّا فِي آخِرِهِنَّ وَيَقُولُ بَعْدَ التَّسْلِيمِ «سُبْحَانَ الْمَلَكِ الْقُدُّوسِ» ثَلَاثًا خَالَفَهُ عَبْدُ الْعَزِيزِ بْنُ عَبْدِ الصَّمَدِ