Create timestamps
By default, the system creates timestamps automatically when the booking status on an entity changes the related Field Service status. Admins can change this behavior on the Field Service Settings in the Timestamp Frequency field.
Work Order / Booking settings
This settings tab lets you define several default values and basic settings related to work orders and bookings.
* Option: Timestamp Frequency
Choose when the system updates the timestamp for a booking.
Reference:
https://learn.microsoft.com/en-us/dynamics365/field-service/booking-timestamps
https://learn.microsoft.com/en-us/dynamics365/field-service/configure-default-settings#work-order--booking-settings