This is a premium feature available with the Astra Pro Addon plugin and old Astra Header (prior to Astra 3.0.0). To use this Pro feature, you need to have the Astra theme along with the Astra Pro Addon installed on your website.
With Astra, it is possible to add a cart icon for the Easy Digital Downloads plugin with simple settings. This article will explain how to add a cart icon in the primary header.
Before that please verify if you have the Easy Digital Downloads plugin installed and activated.
Make sure you have activated the Easy Digital Downloads plugin.
To find the setting, from the WordPress dashboard navigate to Appearance > Customize > Header > Primary Menu > Last Menu in Item and choose Easy Digital Downloads. It will display the Easy Digital Downloads cart icon at the end of the primary menu.
Like the primary header, you can add a mini cart to Above Header and Below Header.
Make sure the Header Sections addon is activated.
Then go to Appearance > Customize > Header > Above Header > Section ( 1/2 ) and choose Easy Digital Downloads.
Astra Pro’s Easy Digital Downloads add-on provides options to change the cart icon, add styling to it, display cart title and total. After activating the addon the setting can be found in the customizer under Customize > Easy Digital Downloads > General
Apart from the header, you might need to display a mini cart icon anywhere on the site. Easy Digital Downloads addon from Astra Pro Provides Mini Cart Shortcode, that allows you to display the mini cart icon anywhere you want.
Refer to the article here for more information.