Deploying mobile apps to test devices is a crucial step in the development process, allowing developers to identify and resolve issues before public release. Appflow, Ionic's mobile CI/CD solution, facilitates this process by supporting both virtual and real devices. Virtual devices, like Android emulators and iOS simulators, are cost-effective and easy to provision for early-stage and automated testing, while real devices offer reliable testing conditions that mimic actual user experiences. Appflow's new iOS Simulator builds enable quick testing without signing certificates, and its App Previews feature allows for easy installation on test devices via QR codes. For broader pre-release testing, developers can use Google Play's testing tracks or Apple TestFlight, each offering different deployment options and audience reach. Appflow integrates with these platforms, providing seamless deployment to both iOS and Android testers, and supports automated deployments through Appflow Automations. The choice of test devices should consider device popularity and potential compatibility issues, with tools like Browserstack offering useful device usage statistics.