Singers can train their voices without sounding like classical singers. vocal warm up exercises and breathing exercises help singers as they grow older not to lose or damage their voice.
    MacColl advocated vocal warm up exercises, and on that particular subject he was right
Singing chromatic scales can help intonation.
Extending vocal range, can be attained by finding your lowest and highest note then taking an instrument and aiming for a semitone either lower or higher, all this is voice training.