The new payment system requires visitors to obtain a QR code showing proof of payment of the access fee or their exemption (check https://cda.ve.it/en/faq#persons-exempt for info).
To obtain your QR code ahead of your arrival, please visit   https://cda.ve.it/ and follow the instructions.
While there are no physical barriers to enter Venicethe local police may approach you and ask you to show your QR code or any other proof of payment/exemption at any time during your stay. Failure to provide this could result in a fine ranging from €50 to €300.
Please note that MSC Cruises cannot be held liable for non-compliance with the above.