Located under Space > Advanced Search is the settings page related to the search panel added to the toolbar. By default the search panel is disabled.
From this page you can enable/disable the search panel, but also set what and where to search.
The search panel can be triggered with Ctrl + M on both front-end and the back-end.
Note: you can also add widgets to the search panel by going to Appearance > Widgets and add widgets to the “Search Sidebar” area. By default, Space adds three useful widgets that can be used: At a Glance, WooCommerce Status and Recent.