By default, document libraries do not show file extensions. You have to rely on the icon to identify the file type, but multiple extensions can share the same icon. Displaying the file extension is therefore a useful improvement.
- Open SharePoint Designer
- Edit the document library view
- Right-click on the file name and select "Edit Formula"
- Use the following XPath expression
$thisNode/@FileLeafRef - Save changes
Do you have a question or a suggestion about this post? Contact me!