In the question bank, teachers can create test questions:

• create
• edit
• view
• organise into question categories and delete.

Questions in question categories can be made available system-wide, within a course or within a test.
Teachers can access the question collection via the cogwheel icon at the top right > More … (or in the Settings > Course Administration block) > Question collection or within a test.

More information on question collections on moodle.org.