This article explains how to replace the native search bar in the The7 theme by Dream-Theme.
FiboSearch plugin has built-in integration with the The7 theme. It means you can replace the default search bar by selecting a single checkbox.
If you have activated The7 theme or child-theme of The7, you should see the following screen in the plugin settings:
WooCommerce -> FiboSearch -> Starting (tab)
Select the option “Replace all The7 search bars with the FiboSearch.” and the search bar should be replaced.