You can Show/Hide the fields to portal users based on condition match that is set and configured in the “Conditional Settings” for the fields. When the portal user selects a Field, which is set as Conditional Field, the Field which is selected in “Visibility Field” will appear in add/edit of any modules. 
– Priority: Select the priority of the subject from “High”,” Medium”, and “Low”. 
If the customer has selected the “Low” priority, then the Type field will appear while adding the case as per the conditional statements from the Conditional Settings.
– Status: Select the status of the subject from New, Assigned, Closed, Pending Input, Rejected, and Duplicate.
– Case Attachments: Portal user can upload the attachments for the subject.
After adding the details, the portal users can save the case details.