Hospitals receive these invoices in addition to internal reimbursement for accounting, binding and preservation, in order to prepare for future checks. The end of the audit (to check whether there is unreasonable expenditure), customers (check the payment status), and so on often people to check. Sometimes even to turn over how many years ago the invoice, especially annoying.
Do not provide to the tax office (except the tax office to ask). There is also no tax deduction. They are kept on their own.