After you file

..aahhh you have your system set to not show the extensions on the files?   You shouldn't hide them...ever  (opinion)

Follow this to turn them on, and leave them on:  <a rel="nofollow" target="_blank" href="https://www.youtube.com/watch?v=PoTah9YBG2Y">https://www.youtube.com/watch?v=PoTah9YBG2Y</a>

Then rt-click on the problem file...select "rename" from the pop-up menu, and hi-lite the "txt" and change it to "pdf".  Be careful to NOT remove the period "." before the .txt
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*