Music in Top Notch Schools?

Hi, I have been playing the piano for quite a while and (in my opinion) am pretty good at it. I haven’t won any significant competitions through it, so how should I make colleges aware of this?
I’ve heard that there is a “music supplement” what exactly is that?

Yes, you may submit a music supplement. But if you are at that level, you should have at least school district level awards. The admission would be selective before sending the supplement out for professional review. It is not the adcom themselves that evaluate it.