Visitor Visa Extension After 10 Years

[avirneni]

Hello,
My Parents' visitor visa is going to expired in Feb-2020. I have few questions if you could help then it would be great appreciated.

1. They got visa obviously in 2010 so I think they are eligible for interview waiver program. So what are the documents required for that ?
2. When can they apply for renewal?
3. What are the supporting documents required? In my parents case, at first time I have sponsored them and I am on H1-B.But now I got my GC and what documents needed?
4. What is "Drop box" option? is my parents eligible for that ? Because I read somewhere that you can do that too.
Thank you in advance

Thanks
Raj

[Libra_14]

1. They got visa obviously in 2010 so I think they are eligible for interview waiver program. So what are the documents required for that ?

Yes, they will be eligible for IWP.

2. When can they apply for renewal?

Before 6 months of expiry their existing visa.

3. What are the supporting documents required? In my parents case, at first time I have sponsored them and I am on H1-B.But now I got my GC and what documents needed?

Proof that you are in USA legally.

4. What is "Drop box" option? is my parents eligible for that ? Because I read somewhere that you can do that too.

IWP is also known as Drop box - its the same thing.