Hover your cursor over the Notifications link to see your unread system notifications.
To view details of your notifications and to manage them, click on the Notifications link.
On the My Notifications page, you can view all your (read and unread) notifications, or you can filter by category (FYI, Todo, or Unread). You can select and delete them all or one-by-one.
To change your notification preferences, click on the Notification Preferences button in the top tight corner. Or click on your name link and on the Notification Preferences link.
You can access the notification preferences also from your Account Settings. See Managing Your Account for more info.
On the My Account Notification Preferences page, select the radio buttons for the items that you want to receive any or all of the notification types: online (to do list) or email.
If you have an SMS-capable device and you validate your phone number, you can also choose to receive notifications as short text messages via SMS. See Enabling or Disabling Two-Factor Authentication for more info.
You also receive notifications displayed in a green bar following certain actions, for example: