If you are in your file explorer: 1. Right click on the file that you want to know what file it is 2. slect "properties" 3. It should show "file type:"
To identify a file type, just place your mouse cursor over a target file and right click. An option list will pop up. Select "Properties" from the option list. A "Properties" window will appear. In the "General" tab, look for "Type of file" to identify the file type. You will also see extension of the current file type.
Besides, right below the "Type of file", there is an option "Open with" along with a default program set to open the file. From there we know the current program that used to open that particular file.