How would using GarageBand benefit a person who wants to become a singer/rapper

What different techniques can be used when creating a song?

I think the hardest part in creating your own songs in GarageBand is making the beat go with the voice.  The reason is I think this is difficult is because sometimes you can't find the beat you have in mind and it doesn't go with your voice. Another challenge was singing in front of my classmates because the person on this side of me <-------- Kept Laughing at Joann and I D':