Do you need to find out who updated a SharePoint Online or OneDrive for Business document? Use PowerShell to search the Office 365 audit log for document events and the complete history is available. Well, at least the last 90 days’ history – or 365 days if you have the necessary licenses.
https://office365itpros.com/2020/05/08/office-365-audit-log-find-who-updated-document/
