curl --request POST \
  --url https://api.zivio.net/api/v3/purchase_orders \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --header 'zivio-tenant-id: <api-key>' \
  --data '{
  "purchase_order": [
    {
      "external_provider": "External System",
      "external_id": "ExSys67687",
      "po_number": "ExSys67687",
      "status": "issued",
      "version": "0",
      "owners": {
        "job": "23",
        "supplier": "23"
      }
    }
  ]
}'

{
  "id": "23",
  "external_provider": "External Service",
  "external_id": "EX67868",
  "po_number": "EX67868",
  "version": 123,
  "status": "<string>",
  "owners": {
    "job": "2",
    "supplier": "2"
  }
}