Surah al-Mulk should be recited abundantly. Recite it and consign the reward to those who have died.

According to hadith:

Surah al-Mulk’s thirty verses (to be recited) regularly, intercede for the reciter to such an extent that they have him forgiven.

According to another hadith:

They continue to ask for their reciter to be forgiven till he is forgiven.

(Tirmidhi # 2900, Abu Dawud # 1400, Ibn Majah # 3786, Musnad Ahmad # 7980)

Sayyiduna Ibn Abbas (RA) narrated:

That Allah’s Messenger (PBUH) said, “i wish that surah al-Mulk should be in the heart of every believer.” and Allah’s Messenger (PBUH) said, “there is a surah in the Book of Allah that has thirty verses. On the day of resurrection, it will intercede for a person till it will get him out of hell and admit him to paradise. That surah is Tabarak (al-Mulk).” (Tirmidhi)