Kibana 4.1 introduced field formatters, a feature that allows users to display data in their preferred format, regardless of how it is stored in Elasticsearch. This functionality enables users to customize the presentation of data, such as displaying date values in a specific format or formatting raw number values like bytes. Field formatters are versatile, allowing users to create links, insert images, and even represent HTTP status codes with creative visuals like HTTP status cats. To format fields, users can navigate through the Kibana interface by selecting the appropriate index pattern, choosing the desired field, and then specifying the format. This feature enhances the usability and visual appeal of data presented in Kibana.