How long it takes if a US citizen apply for parents to get Green card if they are in the US on visitor visa?

Question

and that US citizen is over 21 and she was born here

Answer 1

They will have to go home, and then you can apply.  Are you able to financially sponsor them?  It will take around a year or so if all goes well.

Answer 2

all the process takes less than a year,  just make sure they leave to they country  before the 3 months they can stay.

here you can chack  the forms, prices ans steps to follow to ask them as  alien relatives.

https://egov.uscis.gov/crisgwi/go?action...