In order for you to test Boleto Itaú payment method successfully, you don’t need any given test data.
Boleto Itaú Payment Flow
The customer enters the required details: email address, first name and last name.
The customer receives the Boleto with all the necessary payment details. In order to complete the payment, he needs to print the Boleto and go to a physical bank branch in his area and pay with cash, use online banking, or simply go to an ATM machine.