There is a standard field available to capture the entry description, if you need that information (usually on static exhibits, but it can be used anywhere).
The option is located in Entry Settings, and the field can be set to Invisible (not used), Visible (available and optional) or Visible and Required (the entry cannot be completed if the field is left blank).
Using the standard Entry Description field will allow you to include that information on custom entry cards, and on other standard reports and lists.
If you choose to create a custom field for the description text, that info is NOT available for entry cards, show programs, or other standard reports. It will only be available on custom reports.