How do you stop using icloud?

I want to know how to unsign up for icloud because I don't see the option. I signed up for this because my phone spontaniously deleted over one hundred of my notes, I thought I would use it for back up since I can't get those notes so I figured with icloud the notepad would not be able to do something like that in such a way that I couldn't get the notes back. Anyway, my photo's no longer transfer to my computer.