Google Classroom now allows you to share files Google Drive files that do not belong to you such as a template. This saves teachers and students the extra step of adding files to their drive before sharing in Classroom. This also makes it easier for teachers and students who have multiple Google Drive accounts and may have documents between the files.
When adding files not owned by you, Google Classroom will send a notification that you do not have permission to share the document. Click “Copy” to make a copy of the document in your drive and share the document in Google Classroom.