Adding shortcodes via custom fields

Go to Plugins > Add New and search for "Advanced Custom Fields". Install and activate this plugin.

In your child theme's functions.php file add:

function ghostpool_shortcode_meta( $value, $name ) {
    if ( get_field( $name ) ) {        
        return do_shortcode( get_field( $name ) );
    } else {        
        return $value;
add_filter( 'ghostpool_post_meta_custom_field', 'ghostpool_shortcode_meta', 10, 2 );

Now you can use the Post Meta element. Set the Type setting to Custom Field and in the Custom Field Name give the name of the custom field you'll be adding your shortcode to.

On the desired post create a new custom field with the name you used above and the value as the shortcode.