const options = {method: 'GET'};

fetch('https://api.dolfinai.co/invoices/{id}/pdf', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "type": "<string>",
  "title": "<string>",
  "status": 123,
  "detail": "<string>",
  "instance": "<string>"
}