Where did my .NFO file go?

I searched the forum and didn’t find the information I need. It took me a while, but I finally figured out how to create an .nfo file for a home video of my sons wedding. It now successfully shows up in Kodi (17.1 I think). So I have many more home videos that I want to create .nfo files for. I went to file manager to view the .nfo file as a template and it is no longer there. So where did it go? Not only did I want to review what I created as a template, but I want them all stored somewhere in case my hard drive dies or I need to do a total reinstall. I have all my movies backed up on a different drive, but I use that drive on my windows machine to scan in my movies and test using Kodi on my desktop, for testing only. So Kodi seems to have erased or moved the .nfo from my backup when testing. And the file is also missing from my media system hard drive which is attached to a Raspberry Pi 3. Are these moved and stored somewhere else? Or do I need to keep the nfo files somewhere else away from my Kodi setups on my Windows and Raspberry Pi?
Thanks!
Winnie