How can I edit the risk items for evaluation?

Go to the project page and click the risk items tab. The vocabulary is depending on the project level settings according your use case. 

To add items or categories, click Add New Risk Item or Add new category.

Click the wrench icon to edit the risk or category.

In the session tab, you can choose what risks are shown in the assessment form. 

Click the Recycle Bin to remove the category or risk altogether. Deleting the author also deletes the response data.