If you want to see all the assignment scores for a student in a particular class:

How to see all assignment scores in one course

https://community.canvaslms.com/docs/DOC-26323-how-do-i-view-a-students-grades-page-in-a-course-from-the-gradebook  

If you want to see the overall grades for every class that a student is enrolled in:

How to see all current overall scores for all classes

 Find the student’s user number:

1. Search for the student in canvas admin tool
2. Go to the students page in canvas
3. Look in the address bar for the user number for the student

Type in the URL for the student:

Type https://overlake.instructure.com/users/USERNUMBER/grades into the address bar and press enter to open a page like the one below.

Note: the student's name does not appear on this screen.  If you need to verify which student you are seeing, click on the name of a class.

If you need to see multiple students, write down all the student numbers and update the user number in the address line.