Banco Santander works with a voucher system for allowing deposits to be made at platforms such as online casinos. It is a little slower than some of the other deposit methods because more steps are involved in getting the depositing process completed. It means going to the casino platform first.
The bank has to be presented with a voucher which is first provided by the casino chosen for playing at, that is accepting this form of payment. Once the player receives the voucher for the selected amount to be deposited, they take the voucher to their Santander branch for processing.