Aadhaar card Lost or yet not received then there is an option to download your duplicate copy online from an official website which is also valid officially.
Aadhaar Card Download Duplicate Copy Online by Aadhaar Number
Step-1 first visit official website https://eaadhaar.uidai.gov.in/
Step-2:You Have 2 Options Now,You Can Either Click On Enrollment Id or Aadhaar button PLEASE SKIP THE ENROLLMENT ID OPTION
if you do not have the enrollment id that specifies the date and time you first registered,
Click the Aadhaar Option to put in your Aadhaar Number.