Like most things in Baldur’s Gate, burial is a service.
Nobles and those wealthy enough to afford it are buried in private crypts beneath mansions or temples of their respective patron gods.

Residents who can afford it are buried in Cliffside Cemetery.

The poorest, those unable to afford even that are cremated at the temple of Kelemvor.
Once a tenday, a priest of Kelemvor takes a cart with the ashes to the cliffs west of the city and scatters them into the River Chionthar, saying a final prayer for their souls.