FHMailerBundle
The mailer bundle can be used to simplify the mail sending process in your application. It is a wrapper around the new Symfony mailer component to make it even better.
To quote Symfony's documentation:
Symfony's Mailer & Mime components form a powerful system for creating and sending emails - complete with support for multipart messages, Twig integration, CSS inlining, file attachments and a lot more.
Go have a look at the documentation for information on how to configure any of the mentioned features (and more!): https://symfony.com/doc/current/mailer.html