Riyad us Saliheen: Hadith 938

The Messenger of Allah (ﷺ) led the funeral prayer of a Muslim man in our presence, and I heard him saying "Allahumma inna

[name of the dead person] fi dhimmatika wa habli jiwarika, faqihi fitnatal- qabri; wa 'adhaban-Nari, wa Anta ahlul-wafa'i wal-hamdi; Allahumma faghfir lahu warhamhu, innaka Antal-Ghafur-ur-Rahim

[If the dead person is a woman, one can change hu in some words here with ha]

[O Allah, (so-and-so son of so-and-so) is in Your Protection and inside the surroundings of Your Refuge. Safeguard him from the trial of the grave and the punishment of the Hell. You keep Your Promise and You deserve to be praised. O Allah! Forgive him and be merciful to him. Indeed, You are the Forgiving, the Merciful]."

[Abu Dawud].