WordPress 5.0 brought along a new default theme Twenty Nineteen and a new content editor. The new block editor Gutenberg is now available also on the Helsinki University blogs
Gutenberg allows more control and options for creating posts and pages, as well as embedding some widgets inside the content area. Nevertheless it is a complete overhaul of the classic editor and might get some getting used to. The classic editor still remains as an alternative, and for now the default option also for new blogs.
You can turn on the block editor on your site from “Settings” > “Reading“. To fully take use of all the new features use the Twenty Niteen theme, that has been designed especially to be used with the block editor.