Can you kindly recommend a Dua which I can say, to cleanse my heart and mind and gain forgiveness from Allah. I would really like the best one.
You can recite the following dua:-
‘Allahumma Aati Nafsi Taqwaha
Wa Zakiha Anta Khairu man Zakaaha
Anta waliyuha wa Maulaha’
‘O Allah give my heart its piety
And purify it, for you are the best who can purify it
You are its protector and guardian’.
In order to gain forgiveness from Allah, you should frequently recite the following:-
Astaghfirullaha Rabbi min kulli zambin wa Atubu ilaihi.
‘I seek forgiveness from Allah, my Lord from every sin, and I repent unto Him.’
And Allah knows best,
Mufti Waseem Khan