The functionality that should be used to set up packages is namespace. A namespace is a unique identifier that distinguishes one package from another and prevents naming conflicts with other packages or customizations. A namespace also allows developers to expose their code or components for use by other developers through APIs or web services. A description is not a functionality that should be used to set up packages, but a text field that provides information about the package contents or purpose. A description does not prevent conflicts with other packages or customizations. Allow sharing is not a functionality that should be used to set up packages, but a setting that controls whether users can share records owned by other users within their role hierarchy. Allow sharing does not prevent conflicts with other packages or customizations. Help setting is not a functionality that should be used to set up packages, but a setting that determines whether users can access help documentation for standard Salesforce features or custom features within a package. Help setting does not prevent conflicts with other packages or customizations.