You can send SMS using Node.js and Google Cloud Functions by following these steps: First, create a Twilio account and set up your credentials, then purchase a phone number to use for sending messages. Next, go to the GCP Console and create a new Cloud Function with an HTTPS-based trigger that requires authentication. Add environment variables for your Twilio account credentials to the function. Implement the function using the twilio package in Node.js, which sends SMS based on provided request parameters. Deploy the function and test it by sending a message from the Cloud Shell or locally using the CLI test command. With this setup, you can send SMS messages without provisioning or managing servers, leveraging the power of Google Cloud Functions to create serverless applications.