Cookie

Hello guys. So I recently began to create a new web. Everything looks good except one thing, idk how to create a cookie. What I want that when you choose what you want to do in accessibility tab it will stay in other pages. Photos here:
https://ibb.co/jNpgWK
https://ibb.co/dR10Qe
https://ibb.co/f8xDdz
Mb someone know how to do that? I was searching a lot on google but didn't find anything... This is the code I was writing at the beggining:

<?php
  add_action( 'init', 'accessibility' );
  function accessibility() {
      setcookie($visitor_ip, $ip_value,7 * DAYS_IN_SECONDS);
    }
?>
idk if it is right :D After that I didn't know how to call that code..:
<?php
    if(!isset($_COOKIE[$visitor_ip])) {
    }
    else {
    }
?>

PHP: