Unlike components, which typically are different on every page they appear, modules are small, independent programs that usually appear with the same output on multiple pages of our site.
Modules rarely perform major functions, and usually provide summaries, links to other information, or extra minor features to our site. Modules are executed separately to components, so they cannot pass information directly between each other. As a result, modules are always self-contained, though they may reference tables or files used by components or even other modules. They are also usually displayed on the edges of our site, with the main component or content in the center.
The most simple a module can be is two files. One is an XML file (also called a manifest file), which contains information about the module, such as file lists and parameters that tell Joomla! how to handle the module. The other is a PHP file, and it is in the PHP file that all the code for the execution...