The voucher number is set by ERP when posting

The invoice is posted as usual, but the voucher number is set directly by the ERP (accounting system) through the API.

Semine API

See: Swagger documentation under "Invoice"

PUT /api/v1.0/organizations/{organizationId}/clients/{clientId}/invoices/{invoiceId}/status

{
   "status": "Approved",
   "voucherNumber": "string",
   "message": "string"
}

SEMINE Invoice Details

In this case, the voucher number will only be set after the invoice has been posted to the ERP. In the example below, the invoice has been posted and has received "Voucher number 4" back from the ERP.