Visitor Visa - Income Tax documents

[vidbhi]

Hi

I am calling my parents to US and I have 2 queries:

1. want to know about the Income tax documents. On visitor visa sometimes the Visa Officer may ask for Income tax documents and my parents do not have them, any solution ?

2. At the time of interview token will be issued individually to both of them or they will be given 1 token ?

Please help or give the link in case you know
Thanks in advance.

[immihelp]

1. Why they don't have?
2. One.