This is a premium feature available with Astra Pro Addon plugin. To use these Pro features, you need to have the Astra theme along with the Astra Pro Addon installed on your website.
Header Sections module introduces two header sections (Above Header and Below Header ) in the website header.
You would need to activate Header Sections module from: Appearance > Astra Options > Header Sections
You can find settings under Appearance > Customize > Header
Explore the settings for Header Sections in detail –