| Name | Type | Description | Notes |
|---|---|---|---|
| type | string | Must match the template header's media type. | |
| link | string | Public URL of the asset to send. Must be reachable without auth. | [optional] |
| id | string | A Meta media id (from the media upload endpoint), as an alternative to link. | [optional] |
| filename | string | Document display name shown to the recipient (e.g. "Factura 0001-123.pdf"). document type only; ignored for image/video. | [optional] |