A Muslim may say in Sujud-ul-Sahw and Sujud-ul-Tilawah what they usually say in Sujud (prostration) while offering Salah (Prayer), such as, "Subhana rabbiyal-A`la [All glory is due to my Lord, the Most High]." It can be repeated three times or more; a minimum of one time is mandatory. It is recommended also to say,
"O Allah! To You I have prostrated and in You I have believed, and unto You I have submitted. O Allah! Forgive me all of my sins, the small and large, the first and the last, and the known and the secret. Glory be to You and all praise is due to You. O Allah! Forgive me.
It is also permissible to say,
"Perfect and Glorified (He is), Lord (Part No. 7; Page No. 149) of the angels and the Ruh (i.e. Jibril)."
A Muslim may also invoke Allah with any good invocations they like as they do in the Sujud of the Salah.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.