Once integrated with Salesforce, individual fields can be enabled for synchronization with ClientSuccess on the Integrations Screen, within the Salesforce Sales Cloud section. The fields selected will then be available in the "Salesforce Fields" app on the client screen in ClientSuccess.
Other custom fields can be enabled by submitting a request to ClientSuccess via the messenger chat button bottom-right of screen. Once set up, these fields will be available in the Filters and Columns menus.