Most cemeteries require that the ashes are placed inside an urn vault before burial. An urn burial vault is designed to withstand the pressure of the soil and heavy equipment used by the cemetery grounds crew so that the urn does not collapse from the weight. (It’s worth noting that caskets are also placed inside a burial vault.)
Some families leave their loved one’s ashes in the plastic bag used by the cremation provider. They place the bag directly inside the cremation urn vault for burial.
Others may purchase a special urn to display during their loved one’s services. They will then place the cremation urn inside the urn burial vault that is required by the cemetery.