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 avaialble with Astra Pro plugin.

Primary Header Colors with Astra Theme

As mentioned above, global colors available under Appearance > Customize > Global > Colors will be applied to 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.