Twilio is a cloud communication platform that provides programmable messaging, voice, and video services. Twilio Functions As A Service allows developers to develop, deploy, and run event-driven functions in the cloud without maintaining infrastructure. To send Twilio Programmable SMS using the new Twilio CLI, developers need to install the Twilio CLI, create a Twilio account, and configure their project by installing the serverless plugin. The serverless function can then be deployed and used to send SMS messages to specified recipients.