A file’s extension tells the computer what type of file it is. The extension consist of a unique combination of letters and numbers that follow a period at the end of the file name. For example: an Adobe PDF file has the extension .pdf, or a Microsoft Word document will have a .doc or .docx extension. So a Microsoft Word 2010 document would look like word-document.docx if the file extension were showing instead of word-document. The computer keeps a list of known file extensions handy so that it knows how to deal with each extension it may come across.
By default Windows hides file extensions so that the file names are less confusing for non-technical people.
Show File Extensions
- Open the Control Panel from the Start menu.
- Open Folder Options in the Control Panel.
Note: If Folder Options is not available, change View by to Large icons at the top right of the Control Panel.
- Select the View tab in the Folder Options window.
- Uncheck Hide extensions for known file types.
- Click OK to save the changes.
What next? Learn how to change the file’s extension .