Dynamic file who changed each running

Hey, I would like to get help with my issue.
Each Software running, one of my files are changed (Intentionally), and I wonder how can I make the tests which is every process changed the file name, didn’t succeed to find the right action / parameter / element.
I need to mark the file which get a specific dynamic sign…
I’ve been trying to find the answer for long time without succeed, and that’s why I’m looking for help here.
Thank you!