<?php

defined('ABSPATH') or die('What are you looking for?');
function form_id_show_wp321(){
ob_start();

//This is to pass gform ID
// Global variable for current user ID
// More information: http://codex.wordpress.org/Function_Reference/get_currentuserinfo

$user_ID = get_current_user_id();

// You need to create a new WP query object
// More info: http://codex.wordpress.org/Class_Reference/WP_Query
$post = get_posts( array(
        'author'      => $id,
        'orderby'     => 'date',
        'numberposts' => 1
));

// You get all the current user posts from the query object
$post = $post[0];

// You get the post ID from post object and store it to $gform_post_id variable
$gform_post_id = $post->ID;

?>

<a href="<?php echo 'https://admin.ukoama.com/become-a-client-existing-user/?gform_post_id='.$gform_post_id;?>">UPLOAD YOUR LETTER OF AUTHORITY HERE</a>
<?php

return ob_get_clean();

}

add_shortcode('show-id','form_id_show_wp321');