Booking history is where you can see all changes made to bookings by you or your team. You can also see who created the booking and its initial settings.
To find the booking history:
1) open the booking
2) click "Show booking details"
3) select "Show history"
Besides showing you who made the changes and when the booking history will display the following changes related to the booking:
Time and date
Booking method (hours per day, total hours, % of the day)
Assignee
Notes
Automatic tracking (on/off)
Custom fields