Send any document by public link or uploaded id. Set filename so it shows correctly in the chat.

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Request

curl -X POST "${WHATSAPP_API_URL}/${WHATSAPP_PHONE_NUMBER_ID}/messages" \
  -H "Authorization: Bearer ${WHATSAPP_ACCESS_TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
  "messaging_product": "whatsapp",
  "to": "15551234567",
  "type": "document",
  "document": {
    "link": "https://example.com/invoice.pdf",
    "filename": "invoice.pdf",
    "caption": "March invoice"
  }
}'