I’m not really sure why the IRS would ask to see that since they would already have those records on their side of the street.  I print the transmission stuff when I transmit the returns and print the acknowledgments when they come back.  I also print the e-file history for each client and put it in their file once the return has been accepted.  I have always done that for two reasons

1.  Just  in case a meteor hits my computer

2.  I use Intuit for my tax software - do I need to say more?