curl --request GET \
  --url https://api.example.com/signature/by-external-id/{externalId}

{
  "signatureRequests": [
    {
      "metadata": [
        {
          "key": "<string>",
          "value": "<string>"
        }
      ],
      "id": "<string>",
      "name": "<string>",
      "deliveryMode": "EMAIL",
      "externalId": "<string>",
      "signers": [
        {
          "customerId": "<string>",
          "firstName": "<string>",
          "lastName": "<string>",
          "email": "<string>",
          "phoneNumber": "<string>",
          "yousignId": "<string>",
          "status": "PENDING",
          "documentFields": [
            {
              "documentId": "<string>",
              "anchor": {
                "page": {},
                "x": 123,
                "y": 123,
                "height": 123,
                "width": 123
              },
              "mentions": [
                "<string>"
              ],
              "texts": [
                "<string>"
              ],
              "checkboxes": [
                "<string>"
              ]
            }
          ]
        }
      ],
      "documents": [
        {
          "id": "<string>",
          "type": "ATTACHMENT"
        }
      ],
      "status": "PENDING",
      "signedAt": "2023-11-07T05:31:56Z",
      "isOtp": true,
      "reminderSettings": {
        "delay": 1,
        "maxAttempts": 5.5
      },
      "createdAt": "2023-11-07T05:31:56Z"
    }
  ]
}