Jupiter X theme let you use a default Customizer header and footer or create a new custom header and footer from scratch by using Elementor.
Note: To learn about the difference between built-in header and footer and Elementor’s header and footer template, you can refer to this article.
If you are using a header with default Jupiter X Customizer, a background can be added by following the steps below:
1. From the WordPress left dashboard menu, go to Appearance > Customize.
2. From the Customizer left dashboard, go to the Header menu.
3. In the Styles tab, click on Container.
4. Now you can set a color for the background of your header.
5. Click on x, close the Header window and then Publish the settings.