Windows file extensions help distinguish files that share a similar name but serve different purposes. Before sending a document, make the extension visible and check that it matches what the recipient requested.
Show the extension
In File Explorer, choose View > Show > File name extensions. Microsoft explains that the extension is the part after the period in a filename, such as .xlsx in a spreadsheet name.
Examples include .docx for a Word document, .pdf for a PDF, and .jpg for a JPEG image. A useful filename tells you both what the file contains and what format it uses.
Renaming is not conversion
Microsoft explicitly notes that changing an extension does not convert a file to another format. Renaming “report.docx” to “report.pdf” is therefore not a way to produce a PDF.
Use the application’s appropriate save or export function when a different format is required. Then open the resulting file and inspect it before sending.
Run a pre-send check
- Confirm which format the recipient needs.
- Locate the intended version in File Explorer.
- Read the complete filename and extension.
- Open the file and inspect its content.
- Attach that verified file rather than another similarly named copy.
For example, keep an editable working document and a clearly named exported copy. A date or version label can help you distinguish them without relying on the file icon alone.
Keep identification separate from trust
A visible extension is useful information, but it does not prove that a downloaded file is safe or that its contents are genuine. Consider where the file came from and whether you expected it.
For your own work, a consistent naming habit reduces avoidable confusion. Choose names that remain understandable outside the folder where you created them, especially when files will be passed between several people.
Official reference: Read the manufacturer’s instructions.
Featured image: conceptual illustration, not a device screenshot.