1] Notepad Opening an XFDL file in Notepad is a no-brainer. Right-click on the XFDL file, hover to “Open with” in the context menu, and select Notepad. It will open the XFDL file in the Notepad.

We show you how to open files with no extension in Windows 11/10. You can try these tricks or use one of these free software or online tools.