Need help for b2 visa documents usa

Hi IL's

Iam trying get visa for my parents to usa (b2 visa),i have paid visa fee and not yet booked for visa interview. Iam not sure what documents i have to send them and they have to arrange some documents as well. So iam looking for help,
I dont have income tax documents , i have requested for the copies it will take 60 days, but not sure income tax transcripts would work . Not sure embassy would accept those income tax transcript as a document.
Please suggest me the procedure & list of documents that we need for visitor visa interview.

Appreciate the help

Thanks
Deepa