A Node.js application is created to send WhatsApp messages to multiple recipients using Google Sheets as a data source and Twilio's API for WhatsApp. The application uses a JWT auth client to authenticate with the Google Sheets API, reads data from the spreadsheet, and sends personalized WhatsApp messages to each recipient. The code includes error handling and a recursive function to send messages one by one. The application is run using the `node index.js` command, and the console shows the SIDs of the sent messages.