Preview the Invoice to be Sent as a Model

var client = new RestClient("//einvoice/Send/Model/Preview");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "application/json");
request.AddHeader("Accept", "text/plain");
request.AddHeader("Authorization", "Bearer <API KEY>");
var body = @"{
  "EInvoice": {
    "InvoiceInfo": {
      "UUID": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "TemplateUUID": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "TemplateBase64String": "string",
      "InvoiceType": "SATIS",
      "InvoiceSerieOrNumber": "string",
      "IssueDate": "2022-11-08T12:29:19.181Z",
      "CurrencyCode": "string",
      "ExchangeRate": 0,
      "InvoiceProfile": "TEMELFATURA",
      "DespatchDocumentReference": [
        {
          "IssueDate": "2022-11-08T12:29:19.181Z",
          "Value": "string"
        }
      ],
      "OrderReference": {
        "IssueDate": "2022-11-08T12:29:19.181Z",
        "Value": "string"
      },
      "OrderReferenceDocument": {
        "ID": "string",
        "IssueDate": "2022-11-08T12:29:19.181Z",
        "DocumentType": "string",
        "DocumentTypeCode": "string",
        "DocumentDescription": "string",
        "Attachment": {
          "Base64Data": "string",
          "MimeCode": "string",
          "FileName": "string"
        }
      },
      "AdditionalDocumentReferences": [
        {
          "ID": "string",
          "IssueDate": "2022-11-08T12:29:19.181Z",
          "DocumentType": "string",
          "DocumentTypeCode": "string",
          "DocumentDescription": "string",
          "Attachment": {
            "Base64Data": "string",
            "MimeCode": "string",
            "FileName": "string"
          }
        }
      ],
      "TaxExemptionReasonInfo": {
        "KDVExemptionReasonCode": "string",
        "OTVExemptionReasonCode": "string",
        "OzelMatrahExemptionReasonCode": "string"
      },
      "PaymentTermsInfo": {
        "Percent": 0,
        "Amount": 0,
        "Note": "string"
      },
      "PaymentMeansInfo": {
        "Code": "string",
        "ChannelCode": "string",
        "DueDate": "2022-11-08T12:29:19.181Z",
        "PayeeFinancialAccountID": "string",
        "Note": "string"
      },
      "OKCInfo": {
        "ID": "string",
        "IssueDate": "2022-11-08T12:29:19.181Z",
        "Time": "string",
        "ZNo": "string",
        "EndPointID": "string",
        "DocumentDescription": "string"
      },
      "ReturnInvoiceInfo": [
        {
          "InvoiceNumber": "string",
          "IssueDate": "2022-11-08T12:29:19.181Z"
        }
      ],
      "AccountingCost": "string",
      "InvoicePeriod": {
        "StartDate": "2022-11-08T12:29:19.181Z",
        "StartTime": "2022-11-08T12:29:19.181Z",
        "EndDate": "2022-11-08T12:29:19.181Z",
        "EndTime": "2022-11-08T12:29:19.181Z",
        "DurationMeasureValue": 0,
        "Description": "string"
      },
      "SGKInfo": {
        "RegisterName": "string",
        "DocumentNumber": "string",
        "RegisterCode": "string"
      },
      "LineExtensionAmount": 0,
      "GeneralKDV1Total": 0,
      "GeneralKDV8Total": 0,
      "GeneralKDV18Total": 0,
      "GeneralAllowanceTotal": 0,
      "PayableAmount": 0,
      "KdvTotal": 0
    },
    "CompanyInfo": {
      "TaxNumber": "string",
      "Name": "string",
      "TaxOffice": "string",
      "PartyIdentifications": [
        {
          "SchemeID": "string",
          "Value": "string"
        }
      ],
      "AgentPartyIdentifications": [
        {
          "SchemeID": "string",
          "Value": "string"
        }
      ],
      "Address": "string",
      "District": "string",
      "City": "string",
      "Country": "string",
      "PostalCode": "string",
      "Phone": "string",
      "Fax": "string",
      "Mail": "string",
      "WebSite": "string"
    },
    "CustomerInfo": {
      "TaxNumber": "string",
      "Name": "string",
      "TaxOffice": "string",
      "PartyIdentifications": [
        {
          "SchemeID": "string",
          "Value": "string"
        }
      ],
      "AgentPartyIdentifications": [
        {
          "SchemeID": "string",
          "Value": "string"
        }
      ],
      "Address": "string",
      "District": "string",
      "City": "string",
      "Country": "string",
      "PostalCode": "string",
      "Phone": "string",
      "Fax": "string",
      "Mail": "string",
      "WebSite": "string"
    },
    "BuyerCustomerInfo": {
      "TaxNumber": "string",
      "Name": "string",
      "TaxOffice": "string",
      "PartyIdentifications": [
        {
          "SchemeID": "string",
          "Value": "string"
        }
      ],
      "AgentPartyIdentifications": [
        {
          "SchemeID": "string",
          "Value": "string"
        }
      ],
      "Address": "string",
      "District": "string",
      "City": "string",
      "Country": "string",
      "PostalCode": "string",
      "Phone": "string",
      "Fax": "string",
      "Mail": "string",
      "WebSite": "string"
    },
    "ExportCustomerInfo": {
      "TaxNumber": "string",
      "LegalRegistrationName": "string",
      "PersonName": "string",
      "PersonSurName": "string",
      "Address": "string",
      "District": "string",
      "City": "string",
      "Country": "string",
      "PostalCode": "string",
      "Phone": "string",
      "Fax": "string",
      "Mail": "string",
      "WebSite": "string"
    },
    "InvoiceLines": [
      {
        "Index": "string",
        "SellerCode": "string",
        "BuyerCode": "string",
        "Name": "string",
        "Description": "string",
        "Quantity": 0,
        "UnitType": "string",
        "Price": 0,
        "AllowanceTotal": 0,
        "KDVPercent": 0,
        "KDVTotal": 0,
        "Taxes": [
          {
            "TaxCode": "string",
            "Total": 0,
            "Percent": 0,
            "ReasonCode": "string",
            "ReasonDesc": "string"
          }
        ],
        "DeliveryInfo": {
          "GTIPNo": "string",
          "DeliveryTermCode": "string",
          "TransportModeCode": "string",
          "PackageBrandName": "string",
          "ProductTraceID": "string",
          "PackageID": "string",
          "PackageQuantity": 0,
          "PackageTypeCode": "string",
          "DeliveryAddress": {
            "Address": "string",
            "District": "string",
            "City": "string",
            "Country": "string",
            "PostalCode": "string",
            "Phone": "string",
            "Fax": "string",
            "Mail": "string",
            "WebSite": "string"
          }
        },
        "ManufacturerCode": "string",
        "BrandName": "string",
        "ModelName": "string",
        "Note": "string",
        "OzelMatrahReason": "string",
        "OzelMatrahTotal": 0
      }
    ],
    "Notes": [
      "string"
    ]
  },
  "CustomerAlias": "string"
}";
request.AddParameter("application/json", body,  ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);