You can access this setting via Admin Dashboard > Appearance > Customize > General Settings > Main Header > General.
Header Width: You can set the site header container as full-width or boxed or you can also opt to set a custom width.
Header Search: Enable this option to display search icon on the site header.
Show Cart: Enable this option to display the cart icon on the site header.
Items Spacing: Set the spacing value between the menu items.
Stretch Menu: Enable this option to stretch the menu items across the menu container.
Dropdown Width: Enter the width value for the dropdown menu container.