How to recover file extension (type)

1

I won’t go into details regarding the how, but I am at a position now that I have files with no extensions at all. Can I recover them and how? The folder that I fu had both mp3 and flac files.
And help would be highly appreciated.

2

There are both software tools and website services (upload the files) that can do that.
Should be easy to find if you do a web search on “determine file type without extension”.