The plagiarism checker is deactivated by default. To activate it, simply open or create a document in the Grammarly Editor and click the Plagiarism button in the lower right corner:
Note: If your Grammarly account is provided by your school and you do not see the plagiarism check among the checking options, it means that your institution has opted out of the plagiarism checker with Grammarly. This may be because your school uses another service for plagiarism checking.
If you know the plagiarism checker is supposed to be there but you still don’t see it, you might have accidentally created and logged in to a free Grammarly account. Please make sure to log in to your Premium account to access the plagiarism checker.