Auditing and reporting across all Office 365 services has improved in recent months. Administrators can take advantage of some of the improvements with services available in the Compliance Center, like activity reports that show granular file and folder actions taken by users in a given date range.

Before you can access these activity reports, you have to turn on audit log recording.

1. From the admin center, select Compliance under Admin.
2. In the Compliance Center, select Reports.
3. Click the Office 365 audit log reports link.
4. In the upper left corner of the page, click the Start recording user and admin activities link.

To create an activity report, see instructions on how to Create an Activity Report for a User or File in Office 365.