It is basically copy of yii2-activeform.

The preferred way to install this extension is through composer.

Either run

php composer.phar require --prefer-dist avikarsha/yii2-widget-activeform  "*"

or add

"avikarsha/yii2-widget-activeform ": "*"

to the require section of your composer.json file.

Once the extension is installed, simply use it in your code by :

<?php 
use avikarsha/yii2-widget-activeform/ActiveForm;
?>