How can I get rid of iCloud once forever ?

I would like to know how I can erase the thing called iCloud from my system. I don't want to use anything like that - yet it is obtrusively active. When trying to stop it in system preference, it demands erasing everything from my Notes etc - and it really does it ! Suddenly there is no content in my notes etc. Only when I connect to iCloud again (very strange). When I do new computer installation, suddenlly Safari gets old bookmarks etc. - that I don't want.

My question is - how to erase iCloud from the system without losing the present data and without its connection to some new installations in the future. (during the setup when installing the new system I always disagree with setting iCloud, just mentioning my Apple ID) and it always pushes there something from outside. I simply don't want it.