School-managed Chromebooks are enrolled in the Google Admin console and managed by technology staff at your school or district. These administrators use the Admin console to enforce policies, install apps, and customize device settings. It’s possible your school or district manages student accounts but not devices.
To find out if your student Chromebooks are managed, sign in to one and select the time at the bottom. Look for a message telling you that your device is managed by your school or district. If you don't see that message, talk to your technology staff or school leadership about device management.