locate my current device that i am on

If I just want to see my current location how to locate the computer that I am on do I go to find my iPhone? or is it somewhere else in my cloud account?

I am looking to find out if my iPhone XR battery is dead and I know it's in my home how accurate is the last location that Showed what part of the home it's in

is there a way to boost the batteries somehow online so u can ring once so I can find it?