The article guides developers in building a phone number validator to verify users' phone numbers and check if they are cellphones or landlines before sending SMS using the Twilio service. The tutorial provides a step-by-step guide on how to install the Twilio PHP SDK, configure the client application, and create controller methods to process Twilio requests. It also includes examples of form validation, phone number verification, code verification, and sending SMS. The article concludes by highlighting the ease of use and versatility of the Twilio service for building communication-based projects.