[Health] Invoice and Delivery check boxes, Invoicing, payment term

[Bashar]

Hi,
-what does "invoice" and "delivery" check boxes in every new party creation exactly means?
-suppose a doctor has added a medication under the patient's medication tab, then how to invoice this medication for this specific patient?, since we know that we can invoice the prescriptions that the doctors has prescribed, but how to invoice the medications under medications tab in patient's profile?.
- If some one "not inpatient" and doesn't have an appointment came to the pharmacy of our hospital and purchased a medication, then how to make an invoice for him without registering him as patient?
-I need some explanations about the payment terms especially "lines" of payment terms and how to use it.
-If I want to apply discount on a specific product like specific "bed" for example, then how to do that ?.

Thanks for precise answers :)

regards

Bashar