What is the ruling on giving charity and dedicating its reward to the deceased, how is this done, and does the deceased receive the reward and rejoice in it?

The best thing a living person can do for a deceased one is to give charity on their behalf with the intention that the reward reaches them. Scholars have unanimously agreed that the benefit of charity and supplication reaches the deceased. As for what has been mentioned, that charity is taken to the deceased on a plate of light, this was mentioned in a weak hadith.