Where can I see the HTML-markup

The text with formatting applied is displayed:
  • In the cards of the object, client request, registry;
  • In cards with add. attributes: Document, Event, Participant, Task, User, Client;
  • On the forms of events, tasks, notes;
  • In system events of the Action type;
  • In the history of entity changes;
  • When requesting data in the API.

You can read more how to format text in the article Using HTML-Markup in Fields.