Taslak Faturaya Özel Kod Ataması Yapılır.

var options = new RestClientOptions("https://apitest.nilvera.com")
{
  MaxTimeout = -1,
};
var client = new RestClient(options);
var request = new RestRequest("/einvoice/Draft/SpecialCode", Method.Put);
request.AddHeader("Content-Type", "application/json");
request.AddHeader("Authorization", "Bearer <API KEY>");
var body = {"UUID": ["3fa85f64-5717-4562-b3fc-2c963f66afa6" ],"SpecialCode": "string"};
request.AddStringBody(body, DataFormat.Json);
RestResponse response = await client.ExecuteAsync(request);
Console.WriteLine(response.Content);