The Storefront Hooks Customizer gives you the ability to add content to Storefront’s template hooks through the WordPress Customizer.
This plugin only works with Storefront and Storefront Child Themes
You will be able to add content into the Header, Content, Homepage Template, and Footer sections of the Storefront theme.
Each hook is saved on a per-theme basis, so when you switch themes the options will be blank. If you switch back, you will see the options added back.