Arch is a mobile app that allows teachers to connect with students and parents by sending messages, homework reminders, class notes, and files directly to students' phones. Teachers do not need to share their phone numbers and can collect anonymous feedback from students to help improve their teaching. The app also lets teachers schedule updates and messages for the future. To use Arch, teachers create an account, add classes with unique codes, and share the codes with students so they can subscribe and receive updates from their teachers on their phones.