The plugin must have only one required file that repeats the name of the plugin and has an php extension. Example plugin directory myplugin must have file myplugin.php
This example shows a test hierarchy of a large plugin for WordPress
myplugin.php need have mandatory instructions so that the system understands what the plugin is:
<?php /* Plugin Name: My Plugin Plugin URI: https://mypluginsite.com/ Description: One of best plugins in the planet Version: 1.0 Author: John Author URI: https://facebook.com/john Licence: GPLv2 or later Text Domain: myplugin Domain Path: /lang */