The question bank is a collection of quiz questions for your Moodle site. You will have access to different questions in the bank, depending on your location in your site.
In the following screenshot, the user is in the Outlining course. The user selected the Question bank and is now selecting the group of questions to work with:
Note that the user can select questions that are stored for just this course (Course: Basic Botany), the category in which the course resides (Category: Miscellaneous), or the entire site (System). If the user switched to another course, the questions for this quiz and course would be unavailable. However, questions for the new course would be available. Questions for the system are always available.
If you want the questions that you create for this quiz to be available to other users of the site, create the questions under Question bank and move them to the Category level or the System level. Note that your role determines your access to a question category.
As shown in the Add questions to a quiz section, you can create questions and add them directly to a quiz. As shown in the Adding questions to the question bank section, you can also create questions in the question bank and add them to the quiz later. If you're in a hurry to create questions for a quiz, select Edit quiz and start creating them. You can rearrange them in the question bank later.
You can display questions from one category at a time. To select that category, use the Category drop-down list.
If a question is deleted when it is still being used by a quiz, it is not removed from the question bank; instead, the question is hidden. The Also show old questions setting enables you to see questions that were deleted from the category. These deleted (or hidden or old) questions appear in the list with blue boxes next to them.