Background
In the Grading module, you can manually score the answers to certain open item types. This way, you always have the final say about the scores for questions that cannot be scored completely automatically.
Not all assignments appear in the Grading module, because not all item types can be graded. Grading is only possible for the item types open question, revise text, recording, conjugate verbs, upload file, interpreting and fill gaps in text.
Because you don't always want to grade all assignments that contain one of the supported item types, it's up to the author to decide which assignment should appear in the Grading module.
Procedure
To be able to see an assignment in the Grading module, proceed as follows:
Go to Authoring > Assignments.
Select your assignment.
Click on the Results tab.
Activate the option Enable grading for this assignment.
Result: Your assignment will appear in the Grading module when at least one session has been finished.