Cannot delete training workspace, data files, and report files

Hi Yurii. The first thing here would be that only Admins of workspace can delete them. You need to open the workspace settings to find a button "Delete Workspace on the bottom of the menu".

If you can't delete workspace because of permissions and you want to remove the content, you can go to the workspace, explore the content, one by one mouse over and click the three dots to can find "delete" option.

I hope that helps,