Answer:
Step 1 - Go to Maintenance > User Default Format.
Step 2 - Select Form Type> Select Format > Add User which cannot view this format.
Step 3 - When preview the format that setting not allow then system will prompt out warning message.
Note:
User should purchase "User Default Setting" module then only entitle for this function
Maintenance > Security System Role > Permission > Other Operations
Ensure the Preview Other Report Formats is unticked for this user to view only one report format.