If your Assessment has at least 2 questions of any type, you can choose for each candidate to only be shown a certain number of randomly selected questions of that type.
Open the desired Assessment, click Edit, and then navigate to either the question type. You will see an option to enable or disable random selection, with an input for how many questions you'd like each candidate to be shown.
You cannot change this setting once candidates have already taken your assessment. If you add or remove questions to your Assessment, randomization will automatically be disabled.
The Assessment overview page will indicate how many questions each candidate is shown from the total selection.
On the candidate report, you will also see a banner indicating how many questions each candidate is shown from the total selection.