Using Audacity's fade out effect, you can add professional fades to your audio files with minimal effort. The fade out effect will gradually lower the volume on the section of audio selected, reaching silence at the very end. The fade out tool is almost entirely automated, making it straightforward and intuitive enough for beginners and professionals alike. The fade out tool is found in the Effects menu, with Audacity's many other tools.
Highlight the section of audio you want to fade out to silence. The larger a section you select, the longer and slower the fade effect will be.
Click "Effect," followed by "Fade Out."
Finish your other edits, then click "File" followed by "Save Project" to save the project file, or "Export Audio" to save the file as a working audio file.