<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Models\OnlineMeeting;
use Microsoft\Graph\Generated\Models\JoinMeetingIdSettings;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestBody = new OnlineMeeting();
$requestBody->setStartDateTime(new \DateTime('2019-07-12T14:30:34.2444915-07:00'));
$requestBody->setEndDateTime(new \DateTime('2019-07-12T15:00:34.2464912-07:00'));
$requestBody->setSubject('User meeting');
$joinMeetingIdSettings = new JoinMeetingIdSettings();
$joinMeetingIdSettings->setIsPasscodeRequired(true);
$requestBody->setJoinMeetingIdSettings($joinMeetingIdSettings);
$result = $graphServiceClient->me()->onlineMeetings()->post($requestBody)->wait();