Du'a entrusting the deceased to Allah's care

اللَّهُمَّ إِنَّ فُلَانَ بْنَ فُلَانٍ فِي ذِمَّتِكَ، وَحَبْلِ جِوَارِكَ، فَقِهِ مِنْ فِتْنَةِ الْقَبْرِ وَعَذَابِ النَّارِ، وَأَنْتَ أَهْلُ الْوَفَاءِ وَالْحَقِّ، فَاغْفِرْ لَهُ وَارْحَمْهُ، إِنَّكَ أَنْتَ الْغَفُورُ الرَّحِيمُ

Allahumma inna [say your loved one's name] fi dhimmatika, wa habli jiwarika, faqihi min fitnatil-qabri wa 'adhabin-nar, wa anta ahlul-wafa'i wal-haqq, faghfir lahu warhamhu, innaka antal-Ghafurur-Rahim.

O Allah, [say your loved one's name] is under Your care and protection so protect him from the trial of the grave and torment of the Hellfire. Indeed you are faithful and truthful. Forgive and have mercy upon him, surely You are The Oft-Forgiving, The Most Merciful.

Sunan Abī Dāwūd 3202