To select from a list of file types that you would like to be associated with WavePad, use the menu Home -> Options -> File Types.

For the users of Windows XP, Windows Vista and Windows 7, WavePad is set as the default program.

For the users of Windows 8 and later, WavePad will appear as an available program for selected file types. You may still need to manually set it as your default application through Windows Settings -> Default Apps.