Whenever an invoice is created for a patient (or a contact e.g. an insurance company), their address is copied over into the ADDRESS field on the invoice.
If you later change the patient's address, this will NOT update the invoice address i.e. the invoice address will still be the old address. This behaviour is 100% intentional because it is important to have an accurate record of where and to whom historic invoices were sent.
However, it also causes some users to get confused when they print out an invoice and see an old or incorrect address - especially when the address in the patient (or contact) record is correct and up-to-date.
If you wish to update the address in the Invoice, then simply open the invoice record in the Invoice Editor and click the Update the Address button. The invoice will now print with the latest address.
ADDITIONAL NOTE
It may be that when you created an invoice for a patient/contact, at the time, they had NO address information in their record. This means that the invoice address will also be empty and hence, when printing the invoice, the address will be empty.
To correct this, you need to (a) update the address in the patient/contact record and (b) open the invoice in the Invoice Editor and click the Update the Address button.