Date and Created Date fields for an Activity

1. Each activity has two standard Date fields:
 

Date (ActivityDate) - Indicates one of the following:

This field has a timestamp that is always set to midnight in the Universal Time Coordinated (UTC) time zone. The timestamp is not relevant; do not attempt to alter it in order to accommodate time zone differences.

In addition:

Due Time (ActivityDateTime) For an event only, if IsAllDayEvent is set to False, contains the concerned time.
For more info on Date/Due Time and its relation with Start Date, See also: SOAP API Developer Guide: Event

 

Created Date - Indicates the date the task or event was created. In many cases, the date in Created Date is the same as the Date field. When a user logs a call, for example, by clicking on the Log a Call button from a record, the Created Date and the Date field are the same because this task was not scheduled ahead of time, it was generated as needed.
The Created Date is an Audit field, so is created and maintained by the system. For further information about Audit fields, please refer to the following Article: System Fields

 

2. If you are creating or running a report where the Report Type is "Activities with...." (Accounts, Opportunities, etc.) you find additional Date fields including multiple Created Date fields are also available. Each record within each Object has a standard Created Date field and these report types make them available to the report.

To ensure you are getting the correct "Date" field, use the Fields Quick Find and type "date" or "created date" to identify all date fields (with date in their label) and see which Object the field is associated with.