Composer is a dependency manager for PHP (similar to npm for Node.js or pip for Python). With Composer, you can specify the PHP libraries your project depends on, and it will pull and manage all libraries and dependencies for you. Composer is used in all modern PHP frameworks and platforms such as Laravel, Symfony, Drupal, and Magento. This tutorial explains how to install and use Composer on Ubuntu 20.04.

Source: LXer – How to Install and Use PHP Composer on Ubuntu 20.04