Programmatically: How to create a custom module in Magento 2

Step 1: Create a new directory

Create a new directory within the app/code directory of your Magento 2 project. For example, let's name it MyCompany_MyModule.

Step 2: Create the module declaration file

In the MyCompany_MyModule directory, create a new file called registration.php. This file will contain the module declaration:

	\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    'MyCompany_MyModule',
    __DIR__
);
	

This file tells Magento that this is a module and provides the module name (MyCompany_MyModule) and the directory path (__DIR__, which refers to the current directory).

Step 3: Create the module configuration file

Create a new file called module.xml in the etc directory within the MyCompany_MyModule directory:

This file declares the module and specifies its dependencies (in this case, the Magento_Core module).

Step 4: Create the module's controllers, models, and blocks

You can now create your custom controllers, models, and blocks within the Controller, Model, and Block directories respectively.

For example, let's create a simple controller:

	// MyCompany/MyModule/Controller/IndexController.php

namespace MyCompany\MyModule\Controller;

class IndexController extends \Magento\Framework\App\Action\Action
{
    public function execute()
    {
        // Your code here...
        return $this->getResult();
    }
}
	

Step 5: Add routing for the controller

Create a new file called routes.xml in the etc directory:

This file defines a route for your controller.

Step 6: Update the composer.json file

Add the following line to your composer.json file:

	"psr-4": {
    "MyCompany\\MyModule\\": "app/code/MyCompany/MyModule/"
	

This tells Composer where to find your module's PHP files.

Step 7: Run the command to enable and deploy your module

Run the following commands in your terminal:

	php bin/magento module:deploy --area frontend
	php bin/magento setup:upgrade
	

Your custom module should now be enabled and available in your Magento 2 instance.