How do I make the header smaller?

I would like to make the header smaller as it takes up a large part of the screen.  Also, is it possible to have no header, just the menu on all pages except the homepage?  Selected in the header options to only have it on the front page, but all the other pages still have a big blank square above the content. Site url: https://wcregion.ca I am using Ultimate member plugin with extensions and do not want the header on the UM pages, just the menu.