By default, instructors in a course will receive an email every time a student makes a Turnitin submission within Moodle. If you'd prefer not to receive these emails, you can adjust your settings to stop any emails. This is a Moodle-wide setting and will affect all your courses.
To change your notification preferences, click on your name on the top right of the screen → Preferences → User account → Notification Preferences → Messaging. Scroll down to the sections for Turnitin Assignment and Turnitin plagiarism plugin and uncheck the boxes to prevent emails being send whether you are on or offline.