Card Name: 
Multiple cards (Acta de Nacimiento, Carta de Naturalizacion o Documento migratorio)
Issuing Agency: 
Registro Nacional de la Poblacion
Voluntary or Mandatory: 
Card Purpose: 

Essential for tax declaration, registering with companies, schools, affiliation to any health system, passport, etc.

Additional Information: 

The multiple cards are to be unified in the Clave Única del Registro de Población (CURP), which isn't an ID card, but more like a National Insurance Number.