News posts are intended for communicating information which is time-sensitive, like a new product announcement or details of a holiday sale.
In contrast, Knowledgebase articles are for content which will be useful for a long period of time, like a product troubleshooting guide. If the information in an article is likely to be stale within a week or two, it may be better as a news post.
News posts are shown on the web portal in reverse chronological order, like blog posts.
You can make a news post using the +Add button in the content pane.
News posts contain rich text content. The process of editing and publishing them is the same as for creating Knowledgebase articles.
Remember that your news post is only visible once you save it as Published.
News posts can only belong to one category (but news categories can still be nested).