In order to configure the negative marking for an assessment for an existing course, you can:
1 Click on “Courses” in the side-navigation bar.
2. Select “Content Repository”
3. Once done, click on the “Assessments” tab as shown in the figure.
4. Once done, click on the drop-down indicated by three dots against the assessment for which negative marking setting needs to be configured.
5. Select “Edit” from the drop-down
6. Once done, click on the “Tools” button as shown in the screenshot below.
7. Click on the "Settings" option here.
8. Once done, you can configure the “Negative Marking” setting from your screen.
9. Save once done.