visas – Domestic Traveling while pending H1B extension

My H-1B visa expired on June 30, 2021, and my employer in the US applied for an extension on June 18, 2020. I have a trip within US next week, but my employer has not received the I-797 with the case number. I know that I’m allowed to stay and work in the US for at least 240 days, but I don’t have evidence of having submitted the extension. Can you tell me if it is a risk to travel and what evidence can I show to demonstrate that the extension was submitted? Thanks!