Professionally, "post-event" activities include debriefing, analyzing data, and sending follow-up surveys to measure ROI and improve future planning.
For site owners using The Events Calendar or Divi , it refers to creating a "custom post type" for events, often involving custom fields like start dates or event descriptions. field event
Divi 5 Loop Builder Tutorial: Event Calendar with Custom Fields "post-event" activities include debriefing