How to Archive and Delete a Class in Google Classroom
While there’s no limit for the number of classes you can create with a G Suite or school account, you’ll want to keep the Classroom homepage tidy by displaying only the classes you are actively teaching. When you're done teaching a class, you can archive it to remove it from your Classes page or delete it completely if you'll never need it again.
If you want to delete a class completely, you have to archive it first. You can't directly delete an active class.
On the Archived Classes page, click the class's More button.
You also could create a copy of the class or restore it from this menu.
Be aware that you can't undo a deletion, so make sure it's the right class. Additionally, the class files will remain in Google Drive. If you are done with the files, you will need to manually delete them from your Goggle Drive.
The class is permanently deleted from Google Classroom.