Some people believe that when they die their physical body will turn slowly to dust but their soul will leave at the moment they pass on to begin a new life in some sort of afterworld. Most religious people have some faith in this idea.
The transmigration of souls is I think an early Egyptian belief via a mythology of the gods but there were earlier attempts to 'please the gods' on the journey home by leaving trinkets and food and such like in the grave.
Personally I don't buy this notion and tend to think that once the physical body packs up that's it. Lights out. Fin. End of story. Back to cosmic dust and reinvention through natural processes. Beautiful!!