Hi, I believe the paper you get has the info and link to pay through USCIS. Payment would be online. The fees are separate to any other fee. This fee is to get ur green card mailed to you in us.
I belive for medical it does mention to have compleated the vaccine dose series. However I know for other jabs like hep b and other ones with 2 doses required my done had only one and had to wait 1 month to get 2nd dose. Medical doc or embassy didn't ask anything.
If application is paper then they give envelope otherwise all online. @Ravinder kaur did you receive tracking yet. Any one in chat who can share some info regarding taxes and non residency once you move.