What Is death certificate ?
A death certificate is an official document issued by the government (MCD), which declares cause of death, location of death, time of death and some other personal information about the deceased. There are several reasons why you may need to obtain a death certificate. Most often it's to serve as proof for legal purposes.

A death certificate contains personal information about the person who died that someone close to or knowledgeable about the deceased must provide. This information includes: Full name. Social security number.
What  is need of death certificate ?
Death certificates are needed by financial institutions, banks, vehicle information, 401k retirement plans, and life insurance companies.
In most of the United States, death certificates are considered public domain documents and can therefore be obtained for any individual regardless of the requester's relationship to the deceased.