Twilio Studio is a low-code tool for building complex workflows, including contact centers, and offers extendable and powerful features. A Verify subflow in Twilio Studio allows users to send one-time passcodes via SMS for phone verification or user authentication. To create this subflow, users need a Twilio account and a phone number, as well as access to the Twilio CodeExchange to deploy an OTP project. The subflow includes functions to send and check OTPs using the Verify API, and can be reused in other Studio flows. By publishing the subflow and connecting it to a parent flow, users can test the verification process, protecting sensitive account information or making payments or changes to accounts.