رَبِّ اغْفِرْ لِي وَتُبْ عَلَيَّ إِنَّكَ أَنْتَ التَّوَّابُ الْغَفُورُ

Rabbighfir lee watub 'alayya 'innaka 'Antat-Tawwaabul-Ghafoor

My Lord, forgive me and accept my repentance, You are the Ever-Relenting, the All-Forgiving. Ibn 'Umar (RA) said: It would be counted that at any one sitting, the Messenger of Allah (ﷺ) before getting up would say one hundred times:(The dua is mentioned above)

Reference: Sahih. Tirmidhi: 3434