Do I need to create an invoice account and add my payment information in order to use this addon?

No, we charge the amount to the card on file that you made when making the reservation in our reservation software (FareHarbor). To create the itemized invoice/statements, we utilize our invoice program (https://invoice.keeneradventures.com) and send you a PDF of the detailed invoice. You can access it at any time by visiting the invoice website and creating an account with the same email as on file to view your documents