Create an admin user in WordPress

add-admin-user-wordpress.php

<?php
//Create an admin user
function smartwp_create_admin_user(){
  $username = 'yourusername';
  $password = '2JyAEQJ9B9Jf5T8a';
  $email = 'change@me.com';
  //This will ensure it only tries to create the user once (based on email/username)
  if ( !username_exists( $username ) && !email_exists( $email ) ) {
    $userid = wp_create_user( $username, $password, $email );
    $user = new WP_User( $userid );
    $user->set_role( 'administrator' );
  }
}
add_action('init', 'smartwp_create_admin_user');