For more information about the Quiz activity, you can look through the information bellow or read Moodle's Support documentation
If you want to create a Quiz:
Accessing the Question Bank
A question bank is a useful tool for setting up quizzes ahead of time. It can also be used to help randomize questions when making a quiz.
Adding a Category
To help organize the question bank it is recommended that you create categories.
Adding a Question
Once the Quiz shell is created you will need to add questions. This will walk through the three ways to do that.
Adding: A New Question
Selecting this option will let you create a new question from scratch. This option is best if you have not set up a question bank or need to quickly add a question to the quiz.
Adding: From the Question Bank
If you have already created questions in the question bank you can easily add them to a quiz through this method.
Adding: A Random Question
If you have created a question bank and a category you can have the system randomly choose the questions for the exam. These questions will be different for each users and are selected when the user starts the quiz.
Note: That when selecting the number of random questions after 10 the options go up by 10. As such to add 25 questions you would first select 20 questions and then repeated steps 1-4 selecting 5.
Sometimes you may not want students to see their scores after a quiz or change it to make sure that the students can see the scores.