It's similar to the business offerings Google offers, with access to Gmail, Docs, Sheets, Slides and so on, but it also adds the specialized Google Classroom tool that helps students and teachers stay in sync.
It's meant to keep parents more informed and thus more engaged with what their kids are working on, and this feature sounds like it'll take a minimal amount of effort to make that happen.
The Classroom mobile app now supports the ability to annotate documents, for both students and teachers.
Students can now sketch out things like math problems or create visuals to accompany assignments right on their devices, while teachers can go through and mark up homework like they used to do with the dreaded red marker.
Google Forms, the company's survey / questionnaire tool, also got a pretty significant update.