Submit the invocie PDF, when the order status changes to shipped in your system.
Send the API request invoice_url to invoice PDF or PDF file.
- in case you send the invoice_url - set the Content-Type in request header to application/json
- in case you send the PDF file - set the Content-Type in request header to multipart/form-data and send the payload in form-data layout
Send the invoice amount in gross_amount_cents.
Send invoice ID in external_reference_id.
lines object is optional, but recommended.

The invoice can be sumtitted for the order in status confirmed.
If the invoice amount is equal to the order amount, the order status will change to shipped.
If the invoice amount is lower than the order amount, the order status will change to partially_shipped.
You can submit multiple invoices, if the sum of invoice amounts is lower/equal to the order amount.
If the invoice amount (or sum of all invoice amounts) is higher than the order amount, the API will return 422 error.
external_reference_id must match your payment reference on the legal invoice document.