Using the Canvas built-in Turnitin Review
This guide is for use of the Canvas built-in Turnitin Review feature.
If you are attempting to manage an assignment using the Turnitin External Tool, please follow this guide.
The Canvas built-in Plagiarism Review feature uses Turnitin's framework to do plagiarism checking.
The feature is enabled in any Canvas assignment with Submission Type set to Online, and Online Entry Options Text entry and/or File uploads allowed.

This built-in Canvas feature allows for all of the same plagiarism detection and reporting, but uses other Canvas built-in tools (SpeedGrader, Peer Reviews, etc) to handle grading and feedback instead of Turnitin's Feedback Studio.
Using this new feature will require less setup than using the Turnitin External Tool, which incorporates the Feedback Studio.
With the built-in method, you will only need to handle the Canvas Assignment settings, instead of having additional settings within the Turnitin Assignment.