اللَّهُمَّ إِنَّكَ عَفُوٌّ كَرِيمٌ تُحِبُّ الْعَفْوَ فَاعْفُ عَنِّي
Allahumma innaka 'Afuwwun Karimun tuhibbul-'afwa fa'fu 'anni
O Allah, You are the Pardoner, the Most Generous, and You love to pardon, so pardon me.
This expanded version adds "Karim" (the Most Generous) to the du'a Aisha (RA) was taught for Laylatul Qadr. Al-'Afuww means the One who erases sins completely — not just forgives them, but wipes them out as though they never existed.
Related Du'as
رَبِّ اغْفِرْ وَارْحَمْ وَأَنْتَ خَيْرُ الرَّاحِمِينَ
My Lord, forgive and have mercy, and You are the best of those who show mercy.
Sahihرَبِّ إِنِّي ظَلَمْتُ نَفْسِي فَاغْفِرْ لِي
My Lord, indeed I have wronged myself, so forgive me.
Sahihاللَّهُمَّ إِنِّي ظَلَمْتُ نَفْسِي ظُلْمًا كَثِيرًا وَلَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ فَاغْفِرْ لِي مَغْفِرَةً مِّنْ عِندِكَ وَارْحَمْنِي إِنَّكَ أَنتَ الْغَفُورُ الرَّحِيمُ
O Allah, I have wronged myself greatly, and none forgives sins except You. So grant me forgiveness from Yourself and have mercy on me. Indeed, You are the Forgiving, the Most Merciful.
Sahihأَسْتَغْفِرُ اللَّهَ الَّذِي لَا إِلَٰهَ إِلَّا هُوَ الْحَيُّ الْقَيُّومُ وَأَتُوبُ إِلَيْهِ
I seek the forgiveness of Allah, there is no deity except Him, the Ever-Living, the Sustainer, and I repent to Him.
Sahih