If you live in India, then there is a lot of hype and pressure to get various policies and documents linked to you Aadhar number. Here is a small list I found on how to go about it.
The following banks allow you to login to your Internet Banking account and link you Aadhar number.
ICICI Bank HDFC Bank CitiBank Standard Chartered Bank Corporation Bank Axis Bank SBI
Shares and Mutual Funds
Your demat trading account will have a provision when you login to link Aadhar number. However this doesn’t apply for Mutual Funds. All mutual funds go through Karvy or CAMS, hence you can visit the following links to update your Aadhar.
MAX Life https://buyonline.maxlifeinsurance.com/customer_comm1/nov2017/aadhar/index.html
HDFC Life https://cp.hdfclife.com/Aadhar_Info/Default.aspx
Exide Life https://www.oneinsure.com/faq/how-to-link-aadhaar-to-exide-life-insurance-policy#
Bajaj Allianz https://general.bajajallianz.com/BagicNxt/ValidateAadhaarPAN/LinkDtlsCorpPortalDirect.do
ICICI Lombard https://www.icicilombard.com/link-aadhaar-number
Hope this write-up helps.