2- what an umbrella insurance cover?

General expenses like my liability umbrella policy, office supplies, etc. fall under that "general business" class.

I have liability on the property as well as umbrella but I have thought about insurance what insurance do I need for LLC if I am leasing through it. 

We got a million $ umbrella for a few dollars a month.

My feedback would be get a few rentals under your belt then make your decision, assuming we're talking about rentals, leverage, insurance and umbrella policy should check most of the boxes you're looking for.  

Many people mention having an umbrella policy is a good idea, but would I want the umbrella policy for my LLC that owns the property, or myself?

@Michael Lewicki if you have significant equity then use sn LLC, otherwise probably not just get an umbrella policy.

I've been keeping a $1M umbrella policy + 300k liability with home owners as my protection.  

Talk to insurance agent about umbrella coverage and mitigate most of risk that Properly prepared LLC is meant to avoid.

Many who do this will also purchase an umbrella policy for liability protection.Best of luck!