Typically, you will want to grade activities in Moodle via the activity itself. For example, if you create an assignment, you should grade the assignment by clicking on the assignment itself and reviewing/grading student submissions. For more information about grading assignments and other activities, see the information below.
How do I grade a wiki?
There is no in-built grading facility in the wiki but you can manually add a grade item in the gradebook called (for example) "yourwikiname" and enter your grades there.
The answer: Viterbo Self-Service! See links below: