It depends on the Display Results method you are using. In the Shrtcode emthod, it should do this already for you. In other methods, you are using templates from either your theme or page/grid builder plugin, so it would probably need to be within those.

You would need to make edits to the theme template files. That may be a complex task or a simple one, depending on the theme. The basic structure of an archive post loop looks like this (the wp_query to find the posts is usually done away from the archive template, so assume it is already done):

<?php

if ( $query->have_posts() ) {
	
// do anything here that will appear before the actual posts, like pagination,number of results, etc.

	while ($query->have_posts()) {
		$query->the_post();

// output each post with whatever HTML and content you need

	}

// do anything here that will appear before the actual posts, like pagination,number of results, etc.

} else {
	echo "No Results Found";
}

?>

I have added the part that would show a message. You could make it better by adding HTML etc.