Aadhaar Card is a 12-digit unique identity number that must be obtained by every resident of India. The purpose of UIDAI for issuing Aadhaar to the Indian citizens was to provide them with a document, which they could use as unique identity proof for various purposes. However, do note that not only the residents living in India can apply for Aadhaar, but also those Indians who're living outside India.
The eligibility criteria for Aadhaar card enrolment are as follows:
Any citizen of India residing in India is valid for Aadhaar Card.
Though Aadhaar Card is for adults, Baal Aadhar is issued for children below five years.
Biometric registration for children above five years.
Any non-resident Indian or foreigner residing in India can obtain Aadhaar Card.
It's free of cost to obtain Aadhaar card for all Indian citizens including residents, non-residents, and resident foreign nationals despite their nationality and/or citizenship. Moreover, the whole procedure and the required documents remain the same for everyone. Do note at the time of enrolment the individual must be present in person at any of the Aadhaar card centres in India. In fact, for some NRIs, the Aadhaar will serve as a vital identification proof to help them obtain jobs in the government sectors whenever they return. They'll receive the benefits of government study schemes along with social security schemes, too.