Before sleep the Prophet ﷺ taught reciting Ayat al-Kursi and the last three surahs (Al-Ikhlas, Al-Falaq, An-Nas). The Qur'an reminds us that sleep itself is Allah taking the soul and returning it — a nightly trust placed in His hands.
“Allah takes the souls at the time of their death, and those that do not die [He takes] during their sleep. Then He keeps those for which He has decreed death and releases the others for a specified term. Indeed in that are signs for a people who give thought.”— 39:42 (Saheeh International)
Ask Noor can give you the full bedtime routine from the Sunnah, with the surahs and duas in Arabic and transliteration.
Ask Noor — free on the App Store