اَللَّهُمَّ اغْفِرْ لَهُ وَارْفَعْ دَرَجَتَهُ فِي الْمَهْدِيِّينَ، وَاخْلُفْهُ فِي عَقِبِهِ فِي الْغَابِرِيْنَ، وَاغْفِرْ لَنَا وَلَهُ يَا رَبَّ الْعَالَمِيْنَ، وَافْسَحْ لَهُ فِي قَبْرِهِ، وَنَوِّرْ لَهُ فِيهِ

Allahumm-aghfir lahu [mention the person's name] warfa‛ darajatahu fil-mahdiyyin, wakhlufhu fee ‛aqibihi fil-ghaabireena, waghfir lanaa wa lahu yaa rabbal-‛aalameena, wafsah lahu fee qabrihi wa nawwir lahu feeh

O Allah, forgive – [so-and-so] - and raise his rank among the rightly guided, and be a successor to whom he has left behind, and forgive us and him O Lord of the worlds. Make spacious his grave and illuminate it for him. The Messenger of Allah (ﷺ) came to Abu Salama (as he died). His eyes were fixedly open. He closed them, and then said: (The dua is mentioned above)

Reference: Muslim: 920