Visitor visa extension question

[need_b2]

Hello,
I am looking to extend my mother in law's current stay in USA by one more month.
Can someone please comment on to make sure I understand the process?
1. Extend the return ticket to the desired date.
2. Apply online and fill form I-539 + payment
3. Send the documents- copy of extended return ticket,passport, visa, bank statement, explanation of reason for extension
Also do we have to receive any document as a proof of extension that we need to take with us when my MIL departs US?

Please let me know if this is correct.
Thanks

[immihelp]

Yes, that process is about correct. Please visit https://www.immihelp.com/visitors-visa-extension/ for the complete information step by step.

Once the extension is approved, you will get the approval notice (I-797) and new I-94 form.

[need_b2]

Thanks Admin for the reply. What happens if the new I-94 does not come in time before departing out of USA?
Can we just travel out of USA with some kind of confirmation that we did apply for extension?

Thanks