All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Festivals at graves and mausoleums, including serving and distributing food there, are religious innovations that the Sharee‘ah has prohibited. The Prophet, sallallaahu ‘alayhi wa sallam, said that if a person invents something in religion that it does not include, it will be rejected and be not accepted from the doer. [Al-Bukhari and Muslim]
The Prophet, sallallaahu ‘alayhi wa sallam, also said that every religious innovation is a misguidance. [Muslim]
Some people who do this prefer to use their money and serve food by giving this to the poor people at these locations, believing that whoever does not do this every year will be afflicted by disaster. This is a corrupt belief that has no basis in the Sharee‘ah. Whoever wishes to pay charity on behalf of a dead relative should do so away from graves and mausoleums.
And Allaah Knows best.