Adding code in footer.php

Hi there,

Try adding this as a function:

add_action( 'wp_footer', 'tu_add_custom_script' );
function tu_add_custom_script() { 
?>
    <!-- Codice per accettazione cookie - Inizio -->
	<script type='text/javascript'>
	//<![CDATA[
	(function(window) {
	  if (!!window.cookieChoices) {
	    return window.cookieChoices;
	  }
	  var document = window.document; 
	  var supportsTextContent = 'textContent' in document.body;
	  var cookieChoices = (function() {
	    var cookieName = 'displayCookieConsent';
	    var cookieConsentId = 'cookieChoiceInfo';
	    var dismissLinkId = 'cookieChoiceDismiss';
	    function _createHeaderElement(cookieText, dismissText, linkText, linkHref) {
	      var butterBarStyles = 'position:fixed;width:100%;background-color:#eee;' +
	          'margin:0; left:0; bottom:0;padding:4px;z-index:1000;text-align:center;';
	      var cookieConsentElement = document.createElement('div');
	      cookieConsentElement.id = cookieConsentId;
	      cookieConsentElement.style.cssText = butterBarStyles;
	      cookieConsentElement.appendChild(_createConsentText(cookieText));
	      if (!!linkText && !!linkHref) {
	        cookieConsentElement.appendChild(_createInformationLink(linkText, linkHref));
	      }
	      cookieConsentElement.appendChild(_createDismissLink(dismissText));
	      return cookieConsentElement;
	    }
	    function _createDialogElement(cookieText, dismissText, linkText, linkHref) {
	      var glassStyle = 'position:fixed;width:100%;height:100%;z-index:999;' +
	          'bottom:0;left:0;opacity:0.5;filter:alpha(opacity=50);' +
	          'background-color:#ccc;';
	      var dialogStyle = 'z-index:1000;position:fixed;left:50%;top:50%';
	      var contentStyle = 'position:relative;left:-50%;margin-top:-25%;' +
	          'background-color:#fff;padding:20px;box-shadow:4px 4px 25px #888;';
	      var cookieConsentElement = document.createElement('div');
	      cookieConsentElement.id = cookieConsentId;
	      var glassPanel = document.createElement('div');
	      glassPanel.style.cssText = glassStyle;
	      var content = document.createElement('div');
	      content.style.cssText = contentStyle;
	      var dialog = document.createElement('div');
	      dialog.style.cssText = dialogStyle;
	      var dismissLink = _createDismissLink(dismissText);
	      dismissLink.style.display = 'block';
	      dismissLink.style.textAlign = 'right';
	      dismissLink.style.marginTop = '8px';
	      content.appendChild(_createConsentText(cookieText));
	      if (!!linkText && !!linkHref) {
	        content.appendChild(_createInformationLink(linkText, linkHref));
	      }
	      content.appendChild(dismissLink);
	      dialog.appendChild(content);
	      cookieConsentElement.appendChild(glassPanel);
	      cookieConsentElement.appendChild(dialog);
	      return cookieConsentElement;
	    }
	    function _setElementText(element, text) {
	      if (supportsTextContent) {
	        element.textContent = text;
	      } else {
	        element.innerText = text;
	      }
	    }
	    function _createConsentText(cookieText) {
	      var consentText = document.createElement('span');
	      _setElementText(consentText, cookieText);
	      return consentText;
	    }
	    function _createDismissLink(dismissText) {
	      var dismissLink = document.createElement('a');
	      _setElementText(dismissLink, dismissText);
	      dismissLink.id = dismissLinkId;
	      dismissLink.href = '#';
	      dismissLink.style.marginLeft = '24px';
	      return dismissLink;
	    }
	    function _createInformationLink(linkText, linkHref) {
	      var infoLink = document.createElement('a');
	      _setElementText(infoLink, linkText);
	      infoLink.href = linkHref;
	      infoLink.target = '_blank';
	      infoLink.style.marginLeft = '8px';
	      return infoLink;
	    }
	    function _dismissLinkClick() {
	      _saveUserPreference();
	      _removeCookieConsent();
	      return false;
	    }
	    function _showCookieConsent(cookieText, dismissText, linkText, linkHref, isDialog) {
	      if (_shouldDisplayConsent()) {
	        _removeCookieConsent();
	        var consentElement = (isDialog) ?
	            _createDialogElement(cookieText, dismissText, linkText, linkHref) :
	            _createHeaderElement(cookieText, dismissText, linkText, linkHref);
	        var fragment = document.createDocumentFragment();
	        fragment.appendChild(consentElement);
	        document.body.appendChild(fragment.cloneNode(true));
	        document.getElementById(dismissLinkId).onclick = _dismissLinkClick;
	      }
	    }
	    function showCookieConsentBar(cookieText, dismissText, linkText, linkHref) {
	      _showCookieConsent(cookieText, dismissText, linkText, linkHref, false);
	    }
	    function showCookieConsentDialog(cookieText, dismissText, linkText, linkHref) {
	      _showCookieConsent(cookieText, dismissText, linkText, linkHref, true);
	    }
	    function _removeCookieConsent() {
	      var cookieChoiceElement = document.getElementById(cookieConsentId);
	      if (cookieChoiceElement != null) {
	        cookieChoiceElement.parentNode.removeChild(cookieChoiceElement);
	      }
	    }
	    function _saveUserPreference() {
	// Durata del cookie di un anno
	      var expiryDate = new Date();
	      expiryDate.setFullYear(expiryDate.getFullYear() + 1);
	      document.cookie = cookieName + '=y; expires=' + expiryDate.toGMTString();
	    }
	    function _shouldDisplayConsent() {
	      // Per mostrare il banner solo in mancanza del cookie
	      return !document.cookie.match(new RegExp(cookieName + '=([^;]+)'));
	    }
	    var exports = {};
	    exports.showCookieConsentBar = showCookieConsentBar;
	    exports.showCookieConsentDialog = showCookieConsentDialog;
	    return exports;
	  })();
	  window.cookieChoices = cookieChoices;
	  return cookieChoices;
	})(this);
	document.addEventListener('DOMContentLoaded', function(event) {
	    cookieChoices.showCookieConsentBar('Questo sito utilizza i cookie per migliorare servizi ed esperienza dei lettori. Se continui la navigazione consideriamo che accetti il loro uso.',
	        'OK', '+Info', 'http://www.salutealtop.com/policy');
	  });
	//]]>
	</script>
	<!-- Codice per accettazione cookie - Fine -->
<?php 
}

You should add it using one of these methods: https://docs.generatepress.com/article/adding-php/

It looks like you copied the code from within your email.

Can you try copying it directly from this page?

You can, you’d just need to make you had the appropriate opening and closing PHP tags.

You’d also need to use a child theme and overwrite the entire footer.php file, which is likely overkill for something like this.