ENOfficial
Sulaiman bin Buraidah narrated on the authority of his father (RAA) that the Prophet (ﷺ) taught us that when we visit graves we should say, “Peace be upon you, O believing men and women, O dwellers of this place. Certainly, Allah willing, we will join you. We supplicate to Allah to grant us and you well being.” Related by Muslim.
Source: sunnah.com
Other translations
Arabic
وَعَنْ سُلَيْمَانَ بْنِ بُرَيْدَةَ عَنْ أَبِيهِ قَالَ: كَانَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -يُعَلِّمُهُمْ إِذَا خَرَجُوا إِلَى اَلمَقَابِرِ: { اَلسَّلَامُ عَلَى أَهْلِ اَلدِّيَارِ مِنَ اَلْمُؤْمِنِينَ وَالْمُسْلِمِينَ, وَإِنَّا إِنْ شَاءَ اَللَّهُ بِكُمْ لَلَاحِقُونَ, أَسْأَلُ اَللَّهَ لَنَا وَلَكُمُ الْعَافِيَةَ } رَوَاهُ مُسْلِم ٌ 1 .
sunnah.com