We have found one software suitable in our database for this conversion.
As far as we know, the only possible wpp to mp3 conversion we know of, would be the export of Wavepad audio projects (.wpp) as Windows Media Audio (.wma), typically after some editing of the file has been done.
Done through the default Save/Export function in the program. Unfortunately, no other program can convert wpp to wma, so using WavePad appears to be your only choice.
WPP
A wpp file extension is related to the WavePad, an audio editing program form NCH. A wpp file stores audio data.
WMA
Files with wma extension are audio files in Advanced Systems Format (advanced Streaming Format, Active Streaming Format), which is multimedia container format sed to store multimedia data. A wma file stores audio in Advanced Systems Format container and compressed by Windows Media Audio (WMA) codec.