<?php
use Magento\Framework\App\Bootstrap;

require realpath(__DIR__ . '/../app/bootstrap.php');
$params = $_SERVER;
$params[\Magento\Store\Model\StoreManager::PARAM_RUN_CODE] = 'admin';
$params[\Magento\Store\Model\StoreManager::PARAM_RUN_TYPE] = 'store';

$bootstrap = Bootstrap::create(BP, $params);
$obj = $bootstrap->getObjectManager();

/** @var \Magento\Framework\Encryption\EncryptorInterface $encryptor */
$encryptor = $obj->get(\Magento\Framework\Encryption\EncryptorInterface::class);
echo $encryptor->getHash('YourNewPassword123', true);