Microsoft 365 data fields
Microsoft 365 fields match the type of files you collected and processed. For example, for Microsoft Outlook, email fields include typical email fields (From, To, CC, BCC, and so on). Microsoft Calendar fields include Date Started and Date Ended. The various types of Microsoft Office files include standard fields per document type. For all documents collected via Microsoft 365, the system sets the Source field value to M365 Outlook Calendar, M365 Outlook Email, or M365 OneDrive.
For more information about the fields, refer to Search field reference.