This is a score for voice + piano.
The uppermost line are the notes for the voice.
The grand stave below is what the piano plays.
In this case the melody is doubled in the piano (an octave higher). So the piano part will sound fine without the voice. But in some cases the piano only plays the harmony and additional melodic elements, and you need the voice to make it a finished 'product'.
See this question as well:Piano music with two treble clefs, and notes between staves
Also in this case the grand stave consists of two staves in treble clef instead of the usual treble + bass clef. It does this because the left hand part is relatively high and it is easier to read this way.
See this question as well: Piano: grand staff with two treble clefs. Where to place hands?
Bottom two staves, piano. It follows the convention of putting left hand notes in the lower stave, right hand notes in the upper. The LH is higher than the usual LH range, so it's written using treble clef. Very common.
The very top stave is voice. As is obvious from the character name and printed lyrics!