As SharePoint Online administrator, it is difficult to track changes done on SharePoint sites by administrators, especially when you have multiple administrators.
Well, good news, you can now track changes made for up to the last 30 days.
To do so, connect to your SharePoint Online portal (https://<your tenant>-admin.sharepoint.com) and access the Sites\Active sites blade, there you will see the Your recent actions access just on the right side of the site search
You will need a Syntex – SharePoint Advanced Management license.