My mom has an interview date this month for the visitor visa. She was a permanent resident of USA until last year and embassy took a green card when you went for inquiry since she is leaving in Nepal for last few years and not eligible as the PR.

so, we want my mom to visit USA. What are the documents needed ? I am thinking just to send the invitation letter attn to US embassy for my mom. Are there additional documents required such as financial , travel fare etc.

Her passport has US visa stamp when she came in 2016/2017. That time US embassy has considered her as the US resident due to the medical reason and let her entered in the US even after long stay in Nepal. Please advise. Thank you