AmirabbasSedghiza

It's been 3 months already. If you really have no clue of what to take, how to prove or how much time you have, you should reach out to them and ask them all these questions. I assume the officer would have given you some guidelines of what proof to present when he was telling you that you needed more evidence.

did they give you any paper or anything or send email with instructions, what to do next?
or time frame ,how long you have to submit documents.
if not call embassy and ask them.

to prove domicile in USA she can provide copy of her one or more of these
tax returns
bank account in US bank
utility bill on her name
if she works, letter of employment.