My question is that my father has passed away so I just want to know that can I go to his grave can I Du'aa for him on the grave. Or I have seen many people putting flowers and applying water and lighting candles on the graves of their relatives, is it allowed in our religion? If it isn't then what should I do instead just let me know so that I could increase my knowledge. Thanks and Allaah bless all of you.

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 is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

It is permissible to supplicate at the grave of a dead person, in this regard please refer to Fatwa 83228. However, it is not permissible to put flowers on graves as this is imitating the non-Muslims, and we, as Muslims, are prohibited from doing so. It is also not permissible to water the grave unless this is done for a sound reason, like watering the grave in order to prevent the lions from unearthing it. Similarly, lighting candles in forbidden and this matter is discussed in Fatwa 83848, so please refer to it.  

Allaah Knows best.