In Moodle, you could visit the gradebook setup and then click "add item" to create a placeholder in your gradebook that was not actually connected to any real activity or assignment. You could then enter the grades manually directly in the grader report for this item.

You can do the same thing in Canvas, but the process requires creating a NO-SUBMISSION ASSIGNMENT.

Create a No Submission Assignment

A no submission assignment is an assignment that cannot be completed by students. In essence, it is simply a placeholder in the gradebook. This is the same as adding a manual grade item in Moodle.

Open your Assignments section from the course navigation.
Click +Assignment at the top of the page.
Give the assignment a name.
Click "More Options"
Add the number of points the assignment is worth.
Make sure Submission Type is set to "No Submission".

Assignment button No submission setting options

You do not have to add this assignment to a module. This will prevent students from seeing it in your course but allow you to add the grades in the Grades section of your course for this assignment.

Resources for Setting Up Your Gradebook in Canvas

CREATING ASSIGNMENT GROUPS

Click here to learn how to create assignment groups in your canvas course. Assignment groups allow you to set weights to match your course grading policy.

WEIGHTING ASSIGNMENT GROUPS

Canvas allows you to use a grading policy that automatically weights the graded assignments in each group for the final grade in the course. Click here to learn more about weighting grades in your course.

ADD A MANUAL GRADE ITEM TO GRADES

Just like in Moodle, you can add an item to your grades that can be used as a placeholder for grades rather than an actual activity. Click here to learn how to add a no submission assignment to Grades.