Things to know:
To hide grades for an assignment that has already been graded and is currently displaying grades to students, use the hide grades that were previously posted in the Gradebook guide.
If you want newly-entered grades to be hidden from students, you can set a manual posting policy for an assignment or set a manual posting policy for a course.
For more information, see the Canvas Guides: How do I hide grades for an assignment in the New Gradebook?
Learn more about managing grade visibility in your course and view the interactive Student Grade Visibility Flowchart.