This tutorial provides a step-by-step guide on implementing phone verification using Twilio's Verify API in an iOS application developed with Swift. The process involves setting up a backend server, creating a Verify Service, and integrating the Twilio API into the app. The user is prompted to enter their country code and phone number, which are then used to initiate the verification process via SMS. Upon receiving the verification code, the user enters it into the app, which sends the code back to the Verify API for validation. If the code is valid, the user is taken to a VerificationResultViewController displaying a success message; otherwise, an error message is displayed. The tutorial concludes by outlining additional customizations and next steps for enhancing the verification flow.