There is not pet rule in Islam on how to ask forgiveness in Islam from merciful Allah SWT, though there are ways Islam guides how to seek forgiveness and repent from sins from the Lord of the Universes.

You can ask and you must ask forgiveness and seek repentance from Allah Subhana Wata’ala no matter what word are being used while seeking forgiveness from glorious Lord. Someone might say, 'I want to repent but my sins are too many.' But Allah says:

"Say O my slaves, who have transgressed against themselves! Despair not for the mercy of Allah SWT, verily, Allah SWT forgives all sins. Truly, He is oft forgiving, most merciful." [Az-Zumar: 53]

So, the requirement is of seeking repentance and forgiveness from the sins previously made, consciously or unconsciously, not matter what type of words you’re using to seek forgiveness, and no matter how you are asking for forgiveness.

But there however, you most merciful lord teaches us in Quran how to repent, in the way HE taught Prophet Adam A.S. because HE knows that many of us will forget to seek forgiveness, as Allah SWT says in the Holy Quran,

So say, "Our Lord! Grant us forgiveness and mercy! For You are the Best of those who show mercy."
Quran 23:118
 
Oh my Lord, I have indeed wronged my soul!
Quran 28:16
 
Our Lord! We have indeed believed. Forgive us our sins and save us from the agony of the Fire.
Quran 3:16
 
Our Lord! Condemn us not if we forget or fall into error. Our Lord! Lay not on us a burden like that which You did lay on those before us. Our Lord! Lay not on us a burden greater than we have strength to bear. Blot out our sins, and grant us forgiveness. Have mercy on us. You are our Protector. Help us against those who stand against faith."
Quran 2:286

These were the verses of Quran teaching us how to ask for forgiveness in Islam as we as humans are weak in memory, so Allah SWT managed a reminder for us, how Merciful is He!

Last Updated: 21/7/2015