Turnitin.com and the Turnitin Originality Checker in Canvas allow instructors to check student-submitted assignments against a database of existing journals, books and other written materials (both published and submitted by students)
Turnitin's Similarity Report (formerly called the Originality Checker) is integrated into Canvas as an external tool. By integrating this tool with any Canvas assignment an originality report is generated for each student submission.
Turnitin should be added to the assignment when you create it; however, if an assignment does not yet have any submissions, you can edit the assignment and add Turnitin.
For an LTI Instructors guide index, please see this resource: Canvas LTI - Instructor Categories (turnitin.com)
Interpreting the Similarity Report