Turnitin.com is a system that evalutes student papers for originality. In other words, it is a tool for students and teachers to check for plagiarism (both accidental and intentional). If an instructor has created the assignment in such a way to make the "originality reports" available to the students, here is how a student can access that report:
To access your Turnitin originality report on Canvas, go to your grade book.
Once the Turnitin report is completed, a green icon will appear to the right of the assignment, click the icon
You will be redirected to Turnitin's website, click agree
The originality report will appear on the right side of the page
You can view in your paper where the plagiarism claim is in place