You can switch back to the classic editor by installing the Classic Editor or by disabling the Gutenberg plugin. In fact, the classic Classic Editor editor code, which was not deleted in WordPress 5.0, is just a switch.
How to Switch to Classic Editor in WordPress 5.0 Without any Plugin?
You can very easily disable the Gutenberg Editor in WordPress 5.0, you just need to add the below code in the functions.php file of your theme. You can find the functions.php file in the wp-content/themes directory inside your theme folder. You can also edit the file directly from WordPress, to do so head over to Appearance » Theme Editor and edit the functions.php file. After doing the above step the Gutenberg editor will be disabled and the old Classic Editor will be restored, however, the front-end will still load the relevant style files for the Gutenberg editor and to complete disable those too add the below line of code into your functions.php just below the above code. According to the official WP Blog, the Classic Editor will be completely removed from WordPress in 2021, but you don’t have to worry about it. There will be a full set of Classic Editor editor plug-ins for you to choose and get the Classic Editor back.
Method 2: Using the Official Classic Editor Plugin
You just need to install the plugin and that’s all the Gutenberg Editor is gone. However, if you don’t want tons of plugins into your WordPress installation then the above method also works fine and does the same thing as this plugin do.
