POST /<WHATSAPP_BUSINESS_PHONE_NUMBER_ID>/messages

\{
  "messaging_product": "whatsapp",
  "recipient_type": "individual",
  "to": "<WHATSAPP_USER_PHONE_NUMBER>",
  "context": {
    "message_id": "WAMID_TO_REPLY_TO"
  },

  /* Message type and type contents goes here */

}

curl 'https://graph.facebook.com/v19.0/106540352242922/messages' \
-H 'Content-Type: application/json' \
-H 'Authorization: Bearer EAAJB...' \
-d '
\{
  "messaging_product": "whatsapp",
  "recipient_type": "individual",
  "to": "+16505551234",
  "context": {
    "message_id": "wamid.HBgLMTY0NjcwNDM1OTUVAgASGBQzQTdCNTg5RjY1MEMyRjlGMjRGNgA="
  },
  "type": "text",
  "text": {
    "body": "You'\''re welcome, Pablo!"
  }
}'