A will is a document which acts as commanding document for management of the estate of a deceased person. But to make a will effective one must probate it before the court of law. The appointed executor of the will is the person who has the responsibility to undertake the process of probate.
Under the probate proceedings only it is decided by the court whether the will is a genuine will or a forged piece of document. The burden of proof lies on the propounder who has initiated the probate proceedings. It is the propounder who has to clear all the doubts on the will.