For the Assignee, Creator, Inspector, and Followers, task notifications are enabled by default. To disable them, go to the task card, click on the “three dots” menu at the top-right, and in the menu that opens click the Turn notifications off button. To re-enable task notifications, click once more in the task on the “three dots” menu, and in the menu that opens click the Turn notifications on button. By doing so, you can enable or disable online and email notifications for this task at any time.
When you create a task for yourself, you do not receive a notification. Such notification would be redundant, since it would contain information that you already know.