Let's start with the conventions of the file plugin.php

Let's start this blog with the conventions used to create a simple plugin.
< ?php
/*
Plugin Name: My First Plugin
Plugin URI: http://example.com/wordpress-plugins/my-first-plugin
Description: A short description of my plugin
Version: 1.1
Author: Pierpaolo Romanelli
Author URI: http://pierpaoloromanelli.com
License: GPLv2
*/
? >

The first line is very important, it is useful to recognize the name of your plugin.
The second line is a page where is described what your plugin does.
The Description line is a short description shown in your Plugin Screen of WordPress.
The Version is useful to WordPress to search for new updates.
The author is the name of the author of the plugin.
The URI is the page of the plugin's Author.

Let's us see an example of our plugin: