WordPress divides all page content into editable ‘blocks’, which allows you to quickly create and edit content.
You can drag and drop a block to elsewhere on a page, shift it up or down using arrows, and insert or delete new content anywhere on the page. They are a WYSIWYG editor, what you see is what you get, and how something appears in the editor screen will largely be how it appears on the front end.
Each blog has its own settings and toolbars attached – the block settings appear to the right of the editor screen, whilst the toolbar appears either directly above the individual block, or along the top of the editor screen (you can specify a ‘top toolbar’ as a preference using the three-dotted menu in the top right).
If you can’t see the block settings to the right, then use the three-dotted ‘More options’ menu on any block to Show Block Settings or use the keyboard shortcut Ctrl+Shift+, (that’s a comma).