How do I prevent special characters with Address Ninja?

Open Address Ninja from Apps in your Shopify admin. On the home page, click Block special characters. In the Characters to block card, enter the characters to block in the Block field. Select the fields to check, such as Address line 1 or City. Under Countries, choose All countries, Only these countries, or Except these countries. Under Address, choose Shipping address, Billing address, or Shipping and billing addresses. To block other characters in other fields, countries, or addresses, click Add another list. Click Save and turn on. To change the error message, open the Error message card.