You can install the free plugin from your WordPress dashboard.
Steps:
- Go to Plugins → Add New.
- Search for: QT Header & Footer Builder.
- Click Install Now.
- Click Activate.
- After activation, you can find the plugin settings under Appearance → QT Header & Footer Builder.
There you can create your first header or footer template.
If Elementor is installed, the plugin automatically makes its template post type available for Elementor editing.