We are going to build a very simple extension in Magento 2.  When finished, the extension ‘s output will say ” Hello Weblizar, This is your first hello world Magento Extension! ”  in the block content on a custom frontend route.  Let us learn how to create an extension in magento 2 with hello world as our output. 

Requirement :

At list, you have latest Magento 2 version which is currently 2.1.  Is installed on your local system. 

Before we start a Magento 2 extension development, there are two things people often forget and we recommend you to do:

1.  Disable Magento cache

Disabling Magento cache during development will save you some time because you won’t need to manually flush the cache every time you make changes to your code. 

The easiest way to disable cache is to go to Admin => System => Cache Management => select all cache types and disable them. 

2.  Put Magento into a developer mode

You should put Magento into a developer mode to ensure that you see all the errors Magento is throwing at you. 

In order to do this, open your terminal and go to the Magento 2 root.  From there you should run the following command:

php bin/magento deploy:mode:set developer

How To Create An Extension In Magento:

Creating the extension files and folders:Extension Setup
The first step is to create the extension folder and necessary files required to register a Magento extension. 
1.  Create the following folders:

app/code/Weblizar

app/code/Weblizar/Helloworld

The Weblizar folder is the extension namespace, and Helloworld is the extension name. Note: If you don’t have the code folder in your app directory, create it manually. 

2.  Now that we have an extension folder, we need to create a module. XML file in the app/code/Weblizar/Helloworld/etc folder with the following code:

4.  Open your terminal and go to the Magento 2 root.  Run from there the following command:

php bin/magento setup:upgrade

If you want to make sure that the extension is installed, you can go to Admin => Stores => Configuration => Advanced => Advanced and check that the extension is present in the list or you can open app/etc/config.php and check the array for the ‘Weblizar_Helloworld’ key, whose value should be set to 1. 

Creating a controller

1.  First we need to define the router.  To do this, create a routes. XML file in the app/code/Weblizar/Helloworld/etc/frontend folder with the following code:

In Magento 2, layout files and templates are placed in the view folder inside your extension.  Inside the view folder, we can have three subfolders: adminhtml, base, and frontend. 
The adminhtml folder is used for admin, the frontend folder is used for frontend and the base folder is used for both, admin and frontend files. 

1.  First, we will create a helloworld_index_index. XML file in the app/code/Weblizar/Helloworld/view/frontend/layout folder with the following code: