@Janett
You will find more information here : https://getcomposer.org/doc/00-intro.md
Composer is a tool for dependency management in PHP. It allows you to declare the libraries your project depends on and it will manage (install/update) them for you.
The main advantage, it's install you all the dependencies and allow you to call easily the classes inside our script.
Looking the composer external directory :
guzzlehttp ==> api connect
phpmailer ==> send email
xml-rpc ==> webservice
fpdf ==> invoice
are installed by default.
thank you for this release @ClicShopping