iCloud: Reminders overview
Changes you make to reminder lists are automatically pushed to each of your iOS devices and Mac and Windows computers where you set up iCloud for Reminders (or Tasks on a Windows computer). On your iPhone, iPad, iPod touch, or Mac, changes are pushed to the Reminders app. On your Windows computer with iCloud for Windows installed, changes appear as tasks in Microsoft Outlook. No matter which device you use to create and manage reminders, the changes are updated everywhere.
Reminders also appear in Notification Center on iOS devices and Mac computers.
Access iCloud Reminders from a web browser
If you only see Pages, Numbers, Keynote, and Settings on iCloud.com, your account just has access to iCloud web-only features. To gain access to iCloud Reminders and other iCloud features, set up iCloud on your iOS device or Mac.
If you’re using another iCloud app, click the app’s name at the top of the iCloud.com window, then click Reminders.
When accessing iCloud Reminders, make sure you use a browser recommended in the Apple Support article System requirements for iCloud.