Just now, I got add-on for my wife.
Process only through branch only, and documents required are:
1. Add-on form with primary holder signature
2. Signed PAN & aadhar (latest downloaded from madhaar) of add-on member
3. Aadhar consent form, aadhar digital verification with QR code and then signed by add-on member
Once above documents are submitted then 1-2 weeks time is required to get add-on card. I have to submit above document twice because aadhar copy was old downloaded version.