Sayyid al-Istighfar is the supreme wording of seeking forgiveness taught by the Prophet (peace be upon him): "O Allah, You are my Lord, there is no god but You. You created me and I am Your servant, and I am upon Your covenant and promise 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 but You." He said that whoever recites it during the day with firm conviction and dies that day before evening will be among the people of Paradise, and likewise whoever says it at night with certainty and dies before morning. It is best said in the morning and evening as part of one's daily adhkar.
Evidence — the daleel
Sahih al-Bukhari 6306 Ṣaḥīḥ
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.