To change the format of the music tracks, use audio converters (they are mostly freeware or shareware). For example:
Total Audio Converter – this Converter allows you to change the format of any music track (for example, WAV to MP3, MP3 to OGG, MP3 to AAC, CD to MP3, WMA, WAV, VQF, OGG, APE). The program integrates into the operating system, therefore just select a track, and using the context menu (right mouse button) then click Сonvert to".
FanVista Audio Converter the Converter supports the following formats: MP3, WMA, OGG, WAV, APE, AIFF, AMR, FLAC, AC3, AAC, M4A, MMF, MP2.
FreeRIP – copying tracks from a CD into MP3, WAV, WMA, OGG, FLAC, etc.
For more detailed editing of audio files use an audio editor (there are free and paid). Example: Audio Editor, Free Audio Dub, GoldWave, Sound Forge. With the help of such programs you can "cut" or "paste" the desired fragments of tracks. To change the format of the tracks. To apply to the music of one of the numerous effects.
Use on-line converters if you need to convert a small number of tracks in MP3 format. For example,