Hi @LeslieKirshner-,
Turnitin is generally a paid 3rd party service that almost always requires at least a school/college-level, if not an institution-wide ., license in able to use it with a learning management system like Canvas. If your school/institution has a Turnitin license, you'll probably want to reach out to your local Canvas team (usually in the eLearning / IT / Digital Education areas) to find out how they have integrated it with Canvas, as there are a couple different methods with different ways to access it.
Hope this info helps!
-Chris
