Sayyid al-Istighfar
اللَّهُمَّ أَنْتَ رَبِّي، لَا إِلَهَ إِلَّا أَنْتَ، خَلَقْتَنِي وَأَنَا عَبْدُكَ، وَأَنَا عَلَى عَهْدِكَ وَوَعْدِكَ مَا اسْتَطَعْتُ، أَعُوذُ بِكَ مِنْ شَرِّ مَا صَنَعْتُ، أَبُوءُ لَكَ بِنِعْمَتِكَ عَلَيَّ، وَأَبُوءُ لَكَ بِذَنْبِي، فَاغْفِرْ لِي، فَإِنَّهُ لَا يَغْفِرُ الذُّنُوبَ إِلَّا أَنْتَ
Transliteration: Allahumma anta Rabbi, la ilaha illa anta, khalaqtani wa ana 'abduka, wa ana 'ala 'ahdika wa wa'dika mastata'tu, a'udhu bika min sharri ma sana'tu, abu'u laka bi ni'matika 'alayya, wa abu'u laka bi dhanbi, faghfir li, fa innahu la yaghfirudh-dhunuba illa anta.
Translation: O Allah, You are my Lord. There is no god but You. You created me and I am Your servant, and I am keeping my covenant and promise to You as best I can. I seek refuge in You from the evil of what I have done. I acknowledge Your favour upon me and I acknowledge my sin, so forgive me, for none forgives sins except You.
Source: Sahih al-Bukhari 6306
When to recite: Once in the morning and once in the evening; it can also be said at any time you seek forgiveness.