The Messenger of Allah ﷺ, when he prostrated, would say, "O Allah, to You I have prostrated, to You I have submitted, and in You I have believed. My face has prostrated to the One who created it and shaped it, and who fashioned its form beautifully, and brought forth its hearing and sight. Blessed is Allah, the best of creators."
أخبرنا عمرو بن علي قال حدثنا عبد الرحمن هو ابن مهدي قال حدثنا عبد العزيز بن أبي سلمة قال حدثني عمي الماجشون بن أبي سلمة عن عبد الرحمن الأعرج عن عبيد الله بن أبي رافع
أن رسول الله ﷺ كان إذا سجد يقول اللهم لك سجدت ولك أسلمت وبك آمنت سجد وجهي للذي خلقه وصوره فأحسن صورته وشق سمعه وبصره تبارك الله أحسن الخالقين
Muslim narrated it in Salat al-Musafirin, chapter on the prayer of the Prophet ﷺ and his supplication at night, hadith 202/771, from the hadith of Abdul-Rahman bin Mahdi through this same chain, and it is also found in Kubra, hadith 711.