About: Office 365 Management Activity API

The Office 365 Management Activity API pull information on Exchange and non-Exchange activity across Office 365. From MSDN: The Office 365 Management Activity API provides information about various user, admin, system, and policy actions and events from Office 365 and Azure Active Directory activity logs. Customers and partners can use this information to create new or enhance existing operations, security, and compliance-monitoring solutions for the enterprise.

Information on the reports:

Office 365 service reports
https://support.office.com/en-us/article/office-365-service-reports-overview-0eb00978-e41b-4f4f-a1e2-ff42a28c8871
These are videos

Office 365 Reporting web service
https://msdn.microsoft.com/en-us/library/office/jj984325.aspx

Introduction article.

Activity Reports in the Office 365 admin center
https://support.office.com/en-us/article/Activity-Reports-in-the-Office-365-admin-center-0d6dfb17-8582-4172-a9a9-aed798150263

Documentation:

Office 365 Management APIs Overview
https://msdn.microsoft.com/en-us/office-365/office-365-managment-apis-overview

Get started with Office 365 Management APIs
https://msdn.microsoft.com/en-us/office-365/get-started-with-office-365-management-apis

Office 365 Management Activity API reference
https://msdn.microsoft.com/en-us/office-365/office-365-management-activity-api-reference

Office 365 Management Activity API schema
https://msdn.microsoft.com/en-us/office-365/office-365-management-activity-api-schema

Set up your Office 365 development environment
https://msdn.microsoft.com/office/office365/howto/setup-development-environment

Samples:

Office365APIEditor
https://github.com/Microsoft/Office365APIEditor

O365-InvestigationTooling
https://github.com/OfficeDev/O365-InvestigationTooling

To pull the reports from the UI:

Search the audit log in the Office 365 Security & Compliance Center
https://support.office.com/en-us/article/Search-the-audit-log-in-the-Office-365-Security-Compliance-Center-0d4d0f35-390b-4518-800e-0c7ec95e946c?ui=en-US&rs=en-US&ad=US

Additional references:

Office 365 API reference
https://msdn.microsoft.com/office/office365/api/api-catalog