Any fields saved to the object type as components can be displayed on standard forms. Read more here: Add Fields to an Object Type.
Clicking the icon in the field's top-right corner will open the Edit Component Display window, where you can display the field’s short name or long name.
If required fields have been added to a state, you must ensure these fields have been added to any applicable standard forms. Otherwise users will not be able to view and complete the required fields to transition the object to the next state – UNLESS you click the Bypass Required Fields toggle when editing the transition.Read more here: Edit or Delete a Trigger, Transition, or Action.