With the Astra theme, global colors and typography set for the entire website will be applied to the primary header automatically. In case you are looking for header specific color/typography settings, they are available with Astra Pro Addon plugin.
Primary Header Colors with Astra Theme
As mentioned above, global colors available under Appearance > Customize > Global > Colors will be applied to the header. While with Astra Pro Addon you get an option to set a color for each element in the header.
Primary Header Typography with Astra Theme
Typography set for the site under Appearance > Customize > Global > Typography will be applied to the header content by default. While Astra Pro Addon provides more specific options.