See here to create a rubric and attach it to an assignment. This lesson describes how to use a Rubric to grade student work on an assignment.

You will need to create the outcome and rubric separately before you can align the outcome with the rubric.

Rubrics can be created and stored at both the course-level and at account-levels within an organization. Instructors can access these rubrics and attach them to Assignments, Quizzes and Discussions anywhere in Canvas.

Canvas makes it easy to submit assignments on your iPhone by linking them from Dropbox

Note: The assignment must be uploaded to Dropbox prior to submitting the assignment on the Canvas for iOS app.