Turnitin compares papers against a database of current and archived web pages and a repository of periodicals, journals, publications, and previously submitted papers. The similarity score shows the percentage of the paper's matches to these sources.
Your report will usually be generated within ten minutes and any resubmissions will generate a new report once every 24 hours. A delay in receiving a report may indicate that your lecturer has chosen to provide this after they have posted feedback (contact your lecturer for more information).
You can view your report within your module assignment space in Canvas.
Read more here: Viewing the Similarity Report