OkiOki does not support order forms and therefore does not use them to keep your records. So if you have them, you can just delete them. The invoice of your purchase is sufficient for OkiOki and your bookkeeping.
However, it is possible that OkiOki picks up these order forms in your mailbox or storage folder. Would you rather not have OkiOki pick them up? Then please contact firstname.lastname@example.org. We'll have a look together and see how we can help you.