The recommended and preferred way to create a post on the site is to use the block editor that’s available to all members who are Contributors to the site and which is a bit like a word processor; it allows you control over how your article appears on the site.
WordPress has moved away from its old editor which relied on the user occasionally having to know a bit about mark-up language to an approach much more akin to page layout software. They’ve called this Gutenberg. This website now uses Gutenberg as it’s default editor, although many of the posts and pages were created originally using the WordPress Classic Editor. This video, created before the release of WordPress 5 (currently as I write this the site is on 5.4) is a good introduction to the features of the editor.
The basic building block of the new editor is the concept of Blocks. Here’s an introductory video that explains what Blocks are and how to use them in WordPress. Although you’ll be fed up with the word Blocks by the time you’ve finished watching it, it is the best introductory video I’ve found on the subject and is well worth a watch …
… and here’s another on How to Position an Image next to Text …
… and another on How to use the Gutenberg Column Blocks (the title page is wrong) …
… and finally, one on How to use the Gutenberg Group Blocks …
Of course you may prefer to read How to use Gutenberg, and I really like the tutorials from this site.
Another site to look at is this one, which explains the Gutenberg Interface quite well, guiding you around the screen and what to do and how to do it.
Or if you don’t like the style of the presenter of the videos above, and I can assure you there were others that were much worse, then this Australian voice might suit you better …
So if you feel ready to be an author, just click here and start your authoring experience with Gutenberg.