(Extracts from Al Adab Al Mufrad: by Imam Bukhari)
The Prophet (صلى الله عليه وسلم) said "Sayyid ul Istighfar (the best manner of seeking forgiveness) is:
Allahumma anta rabbi la illaha illa anta khalaqtani wa ana
abduka, wa ana 'ala ahdika wa wa'dika mastata 'tu abu'u
laka bi ni'matika wa abu'u laka bi dhambi, fa'ghfir-li, fa-
innahu la yaghfiru' dh-dhunuba illa anta. Audhu bika min
sharri ma sana' tu.
O Allah, You are my Lord. There is no God but You. You
created me and I am Your slave. I follow Your covenant and
promise as much as I can. I acknowledge Your blessing and I
confess to my sins, so forgive me. Only You can forgive sins.
I seek refuge with You from the evil of what I have done.
If he says it in the evening (believing in it) and he dies, he will enter the Garden or will be one of the people of the Garden.
If he says it in the morning and dies that day - it is the same.
Ibn Umar (RA) said:
"We used to count in the assembly of the Prophet (صلى الله عليه وسلم) that He would repeat this prayer a 100 times:
"Rabbi' ghfir li wa tub 'alayya innaka anta' t-tawwabu r'raheem"
O Lord Forgive me and turn to me (accept my repentance). You are
the One who accepts repentance, the Merciful.
May Allah subhana w'talaa give us the tawfiq to repent for our sins and mistakes (those we know of, those we don't) before it is too late. May He accept our dua'as, purify us and make us amongst those who are worthy of entering the Garden of Paradise. May He remove pride, ignorance, envy, jealousy, hatred from our hearts and help us to ask our fellow brother and sisters, parents, teachers whom we have wronged, for their forgiveness.
Please forgive the author if they have ever wronged you in actions or by their tongue, offended you or not fulfilled your rights.