Same in NL, your employer already supplies the tax service with your wage information, and banks already supply the tax service with year-in/year-out balance in

Same in NL, your employer already supplies the tax service with your wage information, and banks already supply the tax service with year-in/year-out balance information on your accounts. You can login on their portal, verify the pre-filled data on the form, and submit it. You only need to enter your own deductibles, if relevant.