Show/hide page content based on cookie from url parameter

I am looking to show some content on a page based on the on the parameter in a link.

If a link is given to a user then they will see the content of the page, if not using the link, then users will not see the content.

Additionally, I need the users of the link to be able to look on other pages and return to the page where the content is hidden/shown and still see the content.

I have set a cookie in functions.php, that will expire in 30days

add_action('init', 'set_feedback_cookie');   function set_feedback_cookie () {     if (isset($  _GET['feedback'])) {     $  name = 'client_feedback';     $  value=$  _GET['feedback'];     setcookie($  name, $  value, time()+60*60*24*30, "/example-page/", "" , "true" ); } 

The cookie is loaded on to the page (as seen in chrome dev tools),

Now i just need to hide the content on the page. The section to hide has an id #form__feedback.

What code do i need to add to get the content to hide, is this code added to functions.php or to a page template?

Is php or jQuery the best option for doing this?