Astra offers 4 widget layout for the footer.
Settings are available under Appearance > Customize > Footer Builder.

As you can see in the above-attached screenshot, there are 3 sections for the Above Footer, Primary Footer, and Below Footer. On clicking the settings icon for each footer module, you can customize each module as per your requirement.
If you click on the ‘Above Footer’ settings icon, you can see the ‘General‘ and ‘Design‘ options. Under ‘General’, you can select the number of columns, Layout, Inner Elements Layout, width, and height. And under the ‘Design’ tab, you can set the background color and spacing.

Once you select the 4 widget layout for the footer, you can set the widgets for each area under Appearance > Customize > Widgets > Footer Builder Widget 5/6/7/8/9/10. You can choose WordPress default widgets or can add a third-party plugin to add widgets to the list.

Colors & Background for Footer Widget Area
You can set the background color, and border size in the footer under Appearance > Customize > Footer Builder.

Note: The above colors will be applied to default WordPress widgets only. If you are using a third-party plugin to add widgets, you would need to manage colors from the plugin itself.
Typography for Footer Widget Area
Typography options set under Appearance > Customize > Global > Typography > Base Font will be applied to the footer widget area by default.

We provide more styling options in dedicated modules of the Astra Pro Addon plugin. Learn more about the Footer Widgets module of Astra Pro Addon.