Thank you for your comment and for using ‘Kaya QR Code Generator’.
I’m sorry that the UI made you confused. Indeed, the plugin doesn’t have any save button because there are no general settings used in this version. Any Qr Code generated is unique and come from a widget and/or a shortcode.
The Shortcode generator assistant is available on pages, posts, WooCommerce products, and any public custom post types and is used to assist on the shortcode structure construction. The generated shortcode must be pasted on a “shordcode block” or directly in the page content.
Thank you, best regards.