https://www.xperience-group.com/news-item/how-to-check-who-created-an-appointment-in-microsoft-outlook-calendar/
NOTE: This solution applies to Microsoft Outlook 2016/2013/2010.
To solve the problem, you will first need to switch the calendar to the List view and then customise it by adding the Organiser field. Follow the instructions below to do that.
1. Open Microsoft Outlook, go to the Calendar view and choose the View tab from the ribbon.
2. On the View tab, click Change view and choose List (Fig. 1.).
Fig.1. Locating List view in Outlook Calendar
3. The Microsoft Outlook Calendar will now switch to List view (Fig.2.)
Fig.2. Microsoft Outlook Calendar displayed as a list
4. To add the organiser field, go back to the view tab, click change view and go to the manage views section (Fig. 1.). The Manage All Views window will open (Fig. 3.)
Fig.3. Managing Microsoft Outlook calendar views in Outlook
5. In the View Name column, select List and click the modify button on the right. The advanced view settings: List window will open (Fig. 4.)
Fig.4. Modifying the List view
6. Click the Columns button.
7. The show columns window will display. From the Select available columns from drop-down list choose All Appointment fields (Fig.5.)
Fig.5. Editing a view
8. From the Available columns list choose Organizer, click the Add button and then OK. (Fig.6.)
Fig.6. Adding the organiser column to the Outlook Calendar’s view
9. A new From column will be added to the calendar’s list. It will show the name of the user who created the appointment. (Fig. 7.)
Fig.7. The Outlook Calendar’s list view displaying names of users who created appointments
NOTE: although you have added the Organiser field, it will be displayed as the From column.