The W-3 is the cover page or totals page of your W-2s.  It is generated when you do your W2-s.  You can access that info by opening the 5-4-1 Federal Forms window.  But instead of starting a new process, click on the history button at the bottom left.  This will bring up the list of things you have processed through Aatrix.  Look for your 2019 W-2 file.  select it and click edit.  You won't really edit it, but then you will get options to reprint things.  In the future, I always recommend you make pdf files of anything you process in Aatrix for longer retention.  Once you get into future years, the older forms are no longer available even in a look back.

How would you recommend making a pdf of the aatrix file?   I'd prefer to do that but it hasn't let me so far.