If you hit this post, then most probably you were looking to hide Notes Section/Notes Tab. However there is a CRM limitation of having only 8 tabs per form[It can be overridden though].
So sometimes you might want to use that notorious Notes tab but then you don’t want users to see Notes field in there.
So here is a one line of code which takes care of it. Just copy paste it on the Form Load of your entity form and it should do the rest