An elective doctor is a doctor in private practice who does not have a contractual relationship with the health insurance companies.
You pay the fee privately in the office, you receive a fee note for this, which you can then submit to your health insurance for reimbursement. The amount you are reimbursed by the health insurance company depends on the service and the health insurance company. Most private insurance companies reimburse 80-100 percent of the elective medical service provided. The only exception is preventive medical checkups (Vorsorgeuntersuchung), which are billed directly to the respective health insurance company through the elective doctor - in this case, there is no cost for you. Prescriptions are accepted in pharmacies and referrals to X-ray institutes, other specialists or laboratories are accepted as well.