Let Users Add Topics to Records
Where: This feature is available in Lightning communities accessed through Lightning Experience and Salesforce Classic. Communities are available in Enterprise, Performance, Unlimited, and Developer editions.
Why: For example, if support agents are interested in communications standards, they can add the Communications Standards topic to any file that includes communications information. They can also assign the topic to cases, contacts, or any other record that they want to organize under the communications standards theme. Community members can easily view, add, and remove topics from records.
How: Add the Topics component to record detail pages for objects that have topics enabled. Configure the title, the placeholder text that appears in the topic editor, and the number of topics listed before the Show More link appears.