A serverless function that validates phone numbers using the Twilio Lookup API is created and deployed on AWS Lambda. The application uses Python 3.8 as its runtime environment and relies on the Twilio Python Helper library to authenticate with the Twilio servers. The function takes a phone number as input, checks if it's valid, and returns information such as the carrier and caller ID data for the specified number. To test the function locally, the AWS Lambda console is used to create an event dictionary that includes the phone number, which is then passed to the function. A zip file containing the source code and dependencies is created and uploaded to the AWS Lambda console, where it's deployed as a serverless function. The function can be invoked directly or through an API Gateway endpoint.