wordpress add shortcode to html block

<div id="ipad-panel">
    [themify_layout_part id=103]
</div>

// function that runs when shortcode is called
function wpb_demo_shortcode() { 
 
// Things that you want to do. 
$message = 'Hello world!'; 
 
// Output needs to be return
return $message;
} 
// register shortcode
add_shortcode('greeting', 'wpb_demo_shortcode');