This POST endpoint is used to enable postal mailing for a tax form (1099-K, 1099-NEC, or 1099-MISC) that has already been transmitted to the IRS. The form is identified by its submission_id, and the form type is detected automatically. A $1.80 USD postal mailing fee is charged per successful request. Postal mailing can be requested multiple times for the same submission (e.g., for re-prints) — each request incurs the fee.

Note: Postal orders can only be created for forms that have been transmitted. For forms not yet transmitted, set is_postal: true on the PUT (update) endpoint instead.