curl --request POST \
  --url https://api.sandbox.monite.com/v1/receivables/{receivable_id}/send \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'x-monite-entity-id: <x-monite-entity-id>' \
  --header 'x-monite-version: <x-monite-version>' \
  --data '
{
  "body_text": "<string>",
  "subject_text": "<string>",
  "language": "<string>",
  "recipients": {
    "bcc": [
      "jsmith@example.com"
    ],
    "cc": [
      "jsmith@example.com"
    ],
    "to": [
      "jsmith@example.com"
    ]
  }
}
'

{
  "mail_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
}