Baha'i practice has no clergy and, as a rule, no congregational prayer. Obligatory daily prayers are said individually, and a gathering of Baha'is that includes prayer has people reading in turn rather than reciting together. The Prayer for the Dead is the single exception in the whole of Baha'i law, and it is worth pausing on why the exception falls where it does.
It is said for any Baha'i who has reached the age of fifteen, before burial. One person reads it aloud while the others present stand in silence. That is the entire obligatory content of a Baha'i funeral. Everything else, the readings chosen, whether there is music, who speaks and for how long, is left to the family and the friends, and Baha'i funerals in different countries look very different from one another as a result.
The point being made by the arrangement is fairly legible. A religion that removes clergy and removes ritual has to be careful about what it puts back, and what it puts back here is the only occasion on which a Baha'i community acts with one voice: the moment one of its members is buried. The prayer itself consists of an invocation followed by verses repeated a set number of times, addressed to God on behalf of the dead person and of everyone present.
The provisions are set out in the Kitab-i-Aqdas, the book of laws, alongside the requirements about burial and the burial ring.