Download and install a MIDI conversion utility if you have not already done so. Consider WIDI Recognition System or intelliScore Ensemble if you do not have such a program in mind.
Launch your MIDI converter. Load your vocal music WAV or MP3 file into your MIDI converter. Select an instrument sound--such as piano or guitar--for your MIDI file to assume. While you are attempting to convert a vocal track, the MIDI rendition will merely convert the sounds and pitch into notes.
Save the MIDI rendition as a new MIDI file.
Download and install a MIDI-to-sheet music transcription utility. Consider Notation Composer of MIDIView Converter if you do not already have such a program in mind.
Launch the MIDI-to-sheet music transcriber. Load the newly rendered MIDI file of your vocal music. Click the "Convert" button or save the file as new sheet music. Doing so completes the vocal music's conversion to sheet music.