Here’s a quick to make sure Windows File Explorer always shows the file extensions to let you know what kind of file you’re looking at. First, type File Explorer Options in your Windows 11 search box and click on the result.
Click the View tab when the File Explorer Options control panel opens.
Then scroll down and untick the box beside Hide extensions for known file types.
Don’t forget to hit apply before you exit.
You should have started “First” by directing us to Control Panel. Using a search for “File Explorer Options” did not give “one result” and most of the options sent us to “search” results, none of which took us to the Control Panel, which is where we need to go. Perhaps your Win10 works differently than mine, but mine is up to date.