If you are expecting that enrollment for aadhaar card is completely online process, let me clear it.
You cannot apply for new aadhaar card online completely. However you can save lots of your time by doing few things that could be done online.
Kindly visit below given link to register for aadhar card online.
Click here to Apply for aadhar card online registration or Visit this UIDAI gov website to apply for Aadhar Card Online registration.