Create a plugin in WordPress

• Create a New Folder:
  In the wp-content/plugins directory of your WordPress installation, create a new folder for your plugin. Name it something unique and descriptive. For this example, let’s call it test-plugin.

• Create the Main Plugin File:
  In the wp-content/plugins directory of your WordPress installation, create a new folder for your plugin. Name it something unique and descriptive. For this example, let’s call it test-plugin.php.

• Add Plugin Information:
  Open the main plugin file (test-plugin.php) and add the following header information at the top:

/*
Plugin Name: Test Plugin
Description: This is a custom WordPress plugin.
Version: 1.0
Author: Your Name
*/

• Define the Plugin Functionality:
  Below the header, you can start defining your plugin’s functionality. For this example, we will display a “Hello, World!” message at the top of the website.

function my_hello_world_function() {
    echo '<div class="hello-world">Hello, World!</div>';
}

• Hook the Function to WordPress:
  To display your “Hello, World!” message, you need to hook your function into WordPress. You can do this by adding the following line to your main plugin file:

add_action('wp_head', 'my_hello_world_function');

• Create an Uninstall Function (Optional):
  To remove any data or options created by your plugin when it’s uninstalled, you can define an uninstall function in your main plugin file:

function my_hello_world_plugin_uninstall() {
    // Add uninstall actions here, if necessary
}
register_uninstall_hook(__FILE__, 'my_hello_world_plugin_uninstall');

• Activate the Plugin:
  Log in to your WordPress dashboard, go to “Plugins,” and you should see your “Test Plugin.” Click the “Activate” button.