The PAN system of identification is a computer-based system that assigns a unique identification number to every Indian tax paying entity. Through this method, all tax-related information for a person is recorded against a single PAN number, which acts as the primary key for storage of information. This is shared across the country and hence no two people on tax paying entities can have the same PAN.
When PAN is allotted to an entity, a PAN Card is provided by the Income Tax Department. While PAN is a number, PAN Card is a physical card that has your PAN as well as name, date of birth, father s or spouses name, and photograph. Copies of this card can be submitted as proof of identity or date of birth.
Your PAN Card is valid for lifetime because it is unaffected by any change in address.