We call the new editor Gutenberg. The entire editing experience has been rebuilt for media rich pages and posts. Experience the flexibility that blocks will bring, whether you are building your first site, or write code for a living.
Gutenberg makes it easy to build rich media pages with blocks. It will revolutionize page building in WordPress.
It’s going to take some getting used to. And in the meantime, people are going to grumble. And complain. And scream. And throw their hands up and shout “I hate it!”
For those people, Jeff Starr made a plugin called Disable Gutenberg, which will disable Gutenberg and enable the old editor. The plugin will also allow you to disable Gutenberg per user, post, post type, or template. If you are not ready for Gutenberg, Starr’s plugin is exactly what you need.
For further options and ways to disable Gutenberg, read Starr’s article How to Disable Gutenberg: Complete Guide.