How do I run an activity report that shows all my notes added in a specified data range?

As long as notes are tracked in the Prophet Opportunity window, you can create an Activity Report that will filter by the preferred date and time. To filter by a date range of the time stamps for the notes, include the field “NoteDateTime” in the selection criteria while choosing fields in the report wizard.

Prophet CRM: New Report Wizard Step 2, View 2

Then, to filter by the date range, click on the Date tab of the Sort Parameters and Filters section. You can filter by a preset period of days (15, 30, 60, 90, etc.) or choose your own date range.

Prophet CRM: Report Manager - Filter Date Range

If notes are tracked in the Contact Manager, you can view those notes, but cannot filter by a date range.