Select the date to define the period. This field depends on the data source that you have selected.
The period date field is the type of date used to calculate the period. For example, if the data source is Contacts, the period date field by default is Date and time of contact. In this case, it means that the period to which the data displayed in the panel refers uses the date and time of the contact.
For example, if the period of the panel is This Month, it means that the data displayed in the panel refers to the contacts that took place this month.