A muslim person who is not married and had relation with a person. What can they do for that sin to be forgiven? Is there a dua for them to say?
As Salaamu Alaikum,
If an unmarried Muslim person had relations with another person who is unmarried, then this is fornication and a very grave sin in Islam. The unmarried person will be required to marry the other person and both of them should continue to repent to Allah, hoping that Allah may accept their repentance. There is no special dua for this, sincere repentance is needed.
And Allah knows best,
Mufti Waseem Khan