Hi, is there any option to show a quiz only to logged …

Hi Rafat,currently, this is something that should be handled by your theme via either a custom post template or a shortcode. It also looks like this free plugin can do what you are asking for: https://en-ca.wordpress.org…

With that said, I think that this will be a great feature to include into the next version of HD Quiz, so thank you for the suggestion!