When you perform mapping between SharePoint list and Outlook, you will see that there are certain mandatory fields including the ‘HTMLBody‘ which stores the email body (or conversation). However, certain organizations have the requirement of only capturing basic email fields and not lengthy body data in order to prevent SharePoint storage from being depleted quickly or may be that you don’t want to allow confidential detailed information to be stored in SharePoint etc. So, under such circumstances, you can enable the option ‘Make the HTMLBody mapping requirement as Optional‘ under Outlook > Issue Tracker toolbar > Team Settings > Advanced Options panel > Attachments tab.
And then, you can go to the mapping panel, and you will see that ‘HTMLBody’ field is no longer marked as mandatory (i.e., the cell background color is no longer red). This means, you can now unmap this HTMLBody field to nothing (empty) for this SharePoint list and save it. Doing this, any new ticket raised in SharePoint from Outlook would no longer bring the email body content to SharePoint.