By default, file extensions are not displayed in Windows Explorer. Yet they are very useful to quickly identify the type of files. Let us see how to enable the display of extensions.
Click Start then Computer.
Click Organize and then Folder and search options. This command displays the Folder Options dialog box. Switch to the View tab. Look for the checkbox Hide extensions for known file types. Untick this checkbox and confirm by clicking OK. As you can see, extensions are now displayed in Windows Explorer.