Use a date range or specific date to find report templates that were created on the given date or date range.
Example
Show burp report that were created in past 6 months.
burpReport.created:[now-6M .. now]
Show burp reports those were created on a specified date.
burpReport.created:"2020-03-20"
Show burp reports which were created after a specified date.
burpReport.created >"2020-03-20"
Show burp reports created between March 2020 to Dec 2020.
burpReport.created:[2020-03-01 .. 2020-12-31]