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.
We have recently released the Header Footer builder in Astra version 3.0.0, due to which you will find some new changes. Please refer to the following article for the same.
Do note you will be able to find the new Typography and Color settings under the Design tab of each section. The following video will give in-depth details.
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.
If you are using Astra Header Footer builder available with Astra version 3.0 and above, refer to the document list here.