You can make multiple copies of assessments in the same course site. For example, you might want to create a new copy of an existing assessment in order to use it as the basis for a new, modified assessment.
Select the Tests & Quizzes tool from the Tool Menu of your site.
Your duplicated assessment will have the title of your original assessment, with a Copy number listed after it.
For example, if you copy an assessment, Quiz #1, for the first time, the copy will be titled Quiz #1 - Copy #1. If you duplicate the original Quiz #1 again without editing the title of Quiz #1 - Copy #1, the newly duplicated assessment will be titled Quiz #1 - Copy #2.
You can edit the Settings of the duplicated assessment, such as its title and availability, by following the steps outlined in How do I view and modify the settings of an assessment?
You may also modify the questions in the duplicated assessment by following the steps outlined in How do I create an assessment in Tests & Quizzes?