Rights to delete items are defined in User Roles. Deletion rights are Item type specific, please follow the steps below to learn more about restricting users to delete.
- In order to restrict users to delete, you have to update User Role settings. Changes will be applied to all users of that Role
- Locate User Role and uncheck “delete” permission for required Item type, users of the respective role won’t be able to delete those Items.
Go to Navigation Menu 
Settings > Projects and Users > Manage Roles and Permissions
You can also add a completely new role for this purpose and customize it accordingly. Learn how to add a new user?
