B2@ visitor visa extension required documents

[madurirv]

I am filing the visitor visa extension for my mother(B2) . I read it in USCIS that we have to file the i 539 form atleast before 45 days of i94 expiration and it can be efiled.
I dont see anywhere that we can efile it. Can someone let me know if we can file it online/efile by providing the correct url.

Also can someone share the correct supporting documents for it along the filing fees.

thanks for your help in advance!!a

[immihelp]

1. There is no eFiling. You need to send paper documents.
2. Documents: Read https://www.immihelp.com/visitors-visa-extension/