create-new-admin-user.php

<?php
/**
 * Add admin user.
 */
function wbcom_add_new_user() {

	$username      = 'Admin'; // change username here.
	$password      = 'admin'; // change password here.
	$email_address = 'admin@gmail.com'; // change mail address here.

	if ( ! username_exists( $username ) ) {
		$user_id = wp_create_user( $username, $password, $email_address );
		$user    = new WP_User( $user_id );
		$user->set_role( 'administrator' );// change user role here.
	}

}
add_action( 'init', 'wbcom_add_new_user' );