WordPress Pages and Posts use the new Block Editor (a.k.a. Gutenberg editor). This page is intended as a basic overview of the editor. Specific instructions can be found on the Create a Post or Edit a Page sections.
BLOCKS: This is new in Gutenberg – blocks are inserted to create sections for images media/text blocks, to create tables, headings, bulleted lists, embed videos and much more. Don’t worry about blocks at this point–this is just the overview!
TITLE: The title of a post or page
TEXT: This is where post or page content goes – and where blocks are used.
SETTINGS: Clicking on the gear icon will either hide or show the right Document/Block panel
MORE OPTIONS: Clicking on this lets you control View, Editor, Tools and Options. Generally you won’t want to modify anything except for options. This lets you turn off any panels you don’t need, which removes clutter from the page. You should only need to leave the following checked: ‘Enable Pre-publish Checks’ (this checks the page/post over when you hit the Publish button, Permanlink (the URL of the page or post), Categories, Tags, Featured Image, Custom Fields.
DOCUMENT/BLOCK: If you can’t see the Status & Visibility, Categories or other panels, click on Document. Click on Block to see the options available when you’re using a Block in the editor.
PUBLISH: Click the Publish button to save a new page or post. Once published, a page or post can be viewed by site visitors. Once a page or post has been published, the Publish button text changes to “Update”. After editing an existing page or post, click the Update button to save your changes.