The plagiarism checker is disabled by default. To check your document for plagiarism against an index of publicly accessible websites and major proprietary databases, simply open or create a document in the Grammarly Editor and click the Plagiarism button in the lower right corner:
If you're using Grammarly for Microsoft Office, please click the Grammarly tab in Word and enable the plagiarism check:
Note: The plagiarism check is not available on mobile devices or tablets at this time.