It was narrated from ʿĀ’ishah that when the Prophet (ﷺ) ﷺ went to bed every night, he would hold his hands together and blow into them, and recite into them (by cupping his hands together) the last three chapters of the Qur'ān. Then he would wipe them over whatever he could of his body, starting with his head and face and the front of his body, and he would do that three times. Reference: Sahih al-Bukhari 5017.
Source: sunnah.com
Other translations
Arabic
عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ إِذَا أَوَى إِلَى فِرَاشِهِ كُلَّ لَيْلَةٍ جَمَعَ كَفَّيْهِ ثُمَّ نَفَثَ فِيهِمَا فَقَرَأَ فِيهِمَا (قُلْ هُوَ اللَّهُ أَحَدٌ) وَ(قُلْ أَعُوذُ بِرَبِّ الْفَلَقِ) وَ(قُلْ أَعُوذُ بِرَبِّ النَّاسِ( ثُمَّ يَمْسَحُ بِهِمَا مَا اسْتَطَاعَ مِنْ جَسَدِهِ يَبْدَأُ بِهِمَا عَلَى رَأْسِهِ وَوَجْهِهِ وَمَا أَقْبَلَ مِنْ جَسَدِهِ يَفْعَلُ ذَلِكَ ثَلاَثَ مَرَّاتٍ.
sunnah.com