Hi there,
At ArcGIS Enterprise 11.1 you can generate asynchronous organization item and member reports by navigating to Organization > Status > Reports when signed in as a member assigned the default administrator role. The member and item reports can be exported as CSV files and can be scheduled to run automatically.

The organization reports I described above differ from the usage reports that you read about in the documentation here.
These content, members and groups usage reports can be viewed by navigating to Organization > Status > Dashboard. They cannot be exported like the organization reports but rather are a dashboard where activity is tracked and displayed. See below:

Let me know if you need further clarification.
Thanks,
Jessica