This is a basic WordPress blog using the block editor.Hitting the Coltish symbol top right gets the worpress dashboard where you can add, publish, delete posts. Clicking Add New gets you into the block editor.
Go down to Appearance and you can change your theme. Live preview where available shows what your blog looks like under other themes. More themes can be added. There are a lot available. I personally use the Divi theme which is very powerful but also very complex, so it is easier to start with the WordPress block editor – Divi replaces this with its own tools. Themes can be changed at any time, but going back from Divi to other themes can be problematic.