Initially, the default header looks like on the following image:

If you want to reduce or enlarge it, you can add the following CSS code to Customize > Additional CSS:
.primary-menu-menu > li {padding: 25px 10px; }.nav-add { padding-bottom: 10px;}.header .logo { padding-bottom: 10px;}.header .header-content-wrapper { padding-top: 10px;}There can be adjusted any padding value according to your needs.