curl --request POST \
  --url https://gateway.3xpay.co/sub-accounts/document \
  --header 'Content-Type: multipart/form-data' \
  --header 'api_key: <api-key>' \
  --header 'api_secret: <api-key>' \
  --form documentType=RG_FRONT \
  --form file='@example-file'

{
  "status": "success",
  "message": "Documento enviado com sucesso.",
  "data": {
    "filename": "rg_frente.jpg",
    "document_type": "RG_FRONT",
    "document_format": "JPG"
  }
}