Quran tells that man gets the reward of his own deeds only. after death, the reward he receives is again of the result of his own good or bad deeds which produce results even after his death like establishing some welfare project or knowledge he shared with people which keeps spread or good kids whom he showed the right path and ask them to do good deeds.

the practice we observe in our society of transmitting Sawaab to dead by reciting Quran or other Azkaar, are later innovation, has no base or legitimacy or validity in Islam.