The size and nature of the estate will determine whether it is necessary for the Executor(s) (where there is a Will) or the Administrator(s) (where there is no Will) to apply to the Probate Court for legal authority to deal with the estate, e.g. to release money held in bank accounts, sell shares, transfer or sell a house.  This legal authority is called the Grant of Representation, specifically a Grant of Probate if there is a Will and a Grant of Letters of Administration if there is not.