Life events like birth, death and marriage that are kept secure under the custody of government authority in the form of certificates are VITAL RECORDS. In some zones, the vital records include records of civil unions or domestic partnership.
In USA, Vital Records Office of the states, capital district and territories and former territories issues birth certificates. Since birth in USA ensures eligibility for American Citizenship, a birth certificate from the Vital Record Office also enables one to obtain US passport. US State department issues a Consular report of birth abroad for children born to US citizens, including births on military bases in foreign countries. These children are also eligible for US passports.
Resources & Collections Free Ancestry Collections | Update on Oct 11, 2018