Hadhrat Abu Bakr Siddique (radhiallahu anhu) reports that Nabi (sallallahu alaihi wasallam) said,
“The person who visits the graves of both his parents, or one of them, and he recites Surah Yaseen at the graveside (of one) or at both of them, they will be forgiven.“
Nabi (sallallahu alaihi wasallam) said that whoever recites this dua once and asks Allah Ta`ala to convey the reward to their deceased parents, there will remain no rights of his/her parents that remains unfulfilled:
اَلْحَمدُ لله رَبِّ الْعَالمين رَبِّ السَّمَوَاتِ، وَرَبِ الأَرْضِ رَبِّ الْعَالمين، وَلَهُ الْكِبْرِيَاءُ فِي السَّمَوَاتِ وَالْأَرْض، وَهُوَ الْعَزِيزُ الْحَكِيم، لله الْحَمدُ رَبِّ السَّمَوَاتِ وَرَبِ الأَرْضِ رَبِّ الْعَالمين، وَلَهُالعَظمةُ فِي السَّمَوَاتِ وَالْأَرْضِ وَهُوَ الْعَزِيزُ الْحَكِيم هُوَ الْمَلِكُ رَبِّ السَّمَوَاتِ وَرَبِّ الأَرْضِ وَرَبِّ الْعَالمين، وَلَهُ النُّورُ فِي السَّمَوَاتِ وَالْأَرْضِ وَهُوَ الْعَزِيزُ الْحَكِيم