Did you install a fullpage.js plugin for WordPress but you cannot use or activate any extension?

That's normal. Fullpage.js extensions do not come with the plugin. They are sold separately. So, if you haven't purchased any extensions, none of the options for extensions will be available on the control panel. They will all be disabled and you won't be able to use them.

If you want to use any extension first you would have to purchase it from the fullpage.js extensions page.

Get a HUGE discount with the extensions bundle!

Once you get an extension you'll receive a license number that you can use on WordPress to use your extension. You can read more about it in the documentation for each of the WordPress plugins: