curl --request GET \
  --url https://api.xplenty.com/{account_id}/api/invoices/{invoice_id} \
  --header 'Accept: <accept>' \
  --header 'Authorization: Basic <encoded-value>'

{
  "id": "<string>",
  "date": "2023-12-25",
  "amount": 123,
  "currency": "<string>",
  "status": "<string>",
  "pdf_url": "<string>"
}