By default, Windows Explorer hides file extensions (e.g., .docx, .pdf, .xlsx, .xml, .png, .mp3), which can make it difficult to see what file types you’re dealing with! One reason this is important is that you don’t want to confuse an executable file (.exe) with any other type of file, both because you want to know when you’re running an executable file and because .exe files can be disguised as other file types for malicious purposes!

As a Word user, you may need to know whether a particular file is in .doc or in .docx format. Here’s how you can set up Windows Explorer to always show file extensions.

In Windows 8/10, do the following:

1. Open File Explorer.

2. On the ribbon, click the View tab. 

3. Check the File name extensions box to toggle file extensions on. (If for some reason you need to hide file extensions again, uncheck the box.) File Explorer will remember this setting until you change it again.

In Windows 7, do the following:

1. Open Windows Explorer.

2. On the toolbar, click Organize, then select Folder and search options from the drop-down menu to bring up the Folder Options dialog.

3. Click the View tab to bring up a list of advanced settings; scroll down to Hide extensions for known file types and uncheck the checkbox.

4. Click Apply, then click OK.