<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Models\Application;
use Microsoft\Graph\Generated\Models\PasswordCredential;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new Application();
$requestBody->setDisplayName('MyAppName');
$passwordCredentialsPasswordCredential1 = new PasswordCredential();
$passwordCredentialsPasswordCredential1->setDisplayName('Password name');
$passwordCredentialsArray []= $passwordCredentialsPasswordCredential1;
$requestBody->setPasswordCredentials($passwordCredentialsArray);
$result = $graphServiceClient->applications()->post($requestBody)->wait();