# How to Request Signature with Authentication
Authentication is the process of verifying the identity of a user, adding an additional layer of security to the document signing process. BoldSign supports multiple authentication methods, including Email OTP, SMS OTP, and access code authentication, to verify the signers.

* **AccessCode** -  A set of alphanumeric characters specified by the sender to the recipient for accessing the document. The sender needs to provide the secure code directly to the recipient.
* **EmailOTP** - A system-generated one-time password delivered to the recipient's mailbox, required to access the document.
* **SMSOTP** - A system-generated one-time password delivered to the recipient's phone number, required to access the document.

## Code snippet

The following sample code snippet requests the EmailOTP authentication to be added to one of the document's recipients.

{% codetab id="codetab1" %}

cURL

```shell
curl -X 'POST' \
  'https://api.boldsign.com/v1/document/send' \
  -H 'accept: application/json' \
  -H 'X-API-KEY: {your API key}' \
  -H 'Content-Type: multipart/form-data' \
  -F 'Signers={
  "name": "hanky",
  "emailAddress": "hankyWhites@gmail.com",
  "signerType": "Signer",
  "signerRole": "Signer",
  "authenticationType": "EmailOTP",
 "formFields": [
   {
     "id": "signid",
     "fieldType": "Signature",
     "pageNumber": 1,
     "bounds": {
       "x": 50,
       "y": 100,
       "width": 100,
       "height": 60
     },
     "isRequired": true
   }
 ]
}
  ' \
  -F 'Files=@{your file}'
```

C#

```csharp
var apiClient = new ApiClient("https://api.boldsign.com", "{Your API key}");
var documentClient = new DocumentClient(apiClient);

var documentFilePath = new DocumentFilePath
{
    ContentType = "application/pdf",
    FilePath = "{Your File path}"
};

var filesToUpload = new List<IDocumentFile>
{
    documentFilePath,
};

var signatureField = new FormField(
   id: "sign",
   isRequired: true,
   type:FieldType.Signature,
   pageNumber: 1,
   bounds: new Rectangle(x: 100, y: 100, width: 100, height: 50));

var formFieldCollections = new List<FormField>()
{
    signatureField
};

var signer = new DocumentSigner(
    signerName: "hanky",
    signerEmail: "hankyWhites@gmail.com",
    formFields: formFieldCollections,
    authenticationType: AuthenticationType.EmailOTP,
    locale: Locales.EN);

var documentSigners = new List<DocumentSigner>()
{
    signer
};

var sendForSign = new SendForSign()
{
    Signers = documentSigners,
    Files = filesToUpload
};
var documentCreated = documentClient.SendDocument(sendForSign);
Console.WriteLine(documentCreated.DocumentId);
```

Python

```python
import requests
import json

url = "https://api.boldsign.com/v1/document/send"

signer_data = {
    "name": "hanky",
    "emailAddress": "hankyWhites@gmail.com",
    "signerType": "Signer",
    "signerRole": "Signer",
    "authenticationType": "EmailOTP",
    "formFields": [
    {
     "id": "signid",
     "fieldType": "Signature",
     "pageNumber": 1,
     "bounds": {
       "x": 50,
       "y": 100,
       "width": 100,
       "height": 60
     },
     "isRequired": true
    }
    ],
    "locale": "EN"
}

payload = {
    'Signers': json.dumps(signer_data)
}

files = [
    ('Files', ('{Your file name}', open('{Your file path}', 'rb'), 'application/pdf'))
]

headers = {
    'accept': 'application/json',
    'X-API-KEY': '{Your API key}'
}

response = requests.post(url, headers=headers, data=payload, files=files)

print(response.text)
```

NodeJS

```js
const axios = require('axios');
const fs = require('fs');
const FormData = require('form-data');

let formData = new FormData();

// Append Signers as an object, not a string
formData.append('Signers', JSON.stringify({
  name: "hanky",
  emailAddress: "hankyWhites@gmail.com",
  signerType: "Signer",
  signerRole: "Signer",
  authenticationType: "EmailOTP",
  formFields: [
    {
      id: "signid",
      fieldType: "Signature",
      pageNumber: 1,
      bounds: {
        x: 50,
        y: 100,
        width: 100,
        height: 60
      },
      isRequired: true
    }
  ],
  locale: "EN"
}));

// Append the file using a specific filename for the 'Files' property
formData.append('Files', fs.createReadStream("{Your file path}"), { filename: '{Your file name}' });
let config = {
  method: 'post',
  maxBodyLength: Infinity,
  url: 'https://api.boldsign.com/v1/document/send',
  headers: { 
    'accept': 'application/json', 
    'X-API-KEY': '{Your API Key}', 
    'Content-Type': 'multipart/form-data',
    ...formData.getHeaders()
  },
  data: formData,
};

axios.request(config)
  .then((response) => {
    console.log(JSON.stringify(response.data));
  })
  .catch((error) => {
    console.error(error);
  });
```
{% /codetab %}

In the above code example, we have enabled EmailOTP authentication. Similarly, please refer to this link for [SMS authentication](https://developers.boldsign.com/how-to-guides/add-sms-authentication/?region=us), and use this link for [Access code authentication](https://developers.boldsign.com/how-to-guides/how-to-provide-access-code-authentication-for-document/?region=us).

**Note:** It's important to note that SMS authentication can be added to the document only for paid plans.