How do I get an executive report or summary for Splunk Enterprise 6.2.4 or where can I find it?
Is there specific information you are trying to present? If so, please say more about it so the community can answer you. If you are just asking in general, than martin_mueller's answer covers it.
Build your report as a dashboard, and either give execs access to the dashboard, or schedule the dashboard for PDF email delivery to execs.
What should the report be built of?
If you are new to Splunk software and don't know how searches, reports, and dashboards work, your best first step is to go through the Search Tutorial. It walks you through the entire workflow with sample data.