Swift Mailer integrates into any web app written in PHP 5, offering a flexible and elegant object-oriented approach to sending emails with a multitude of features.
Swift Mailer is a component-based library for sending e-mails from PHP applications.
Swift Mailer is not an application - it's a library.
To most experienced developers this is probably an obvious point to make, but it's certainly worth mentioning. Many people often contact us having gotten the completely wrong end of the stick in terms of what Swift Mailer is actually for.
It's not an application. It does not have a graphical user interface. It cannot be opened in your web browser directly.
It's a library (or a framework if you like). It provides a whole lot of classes that do some very complicated things, so that you don't have to. You "use" Swift Mailer within an application so that your application can have the ability to send emails.
The component-based structure of the library means that you are free to implement it in a number of different ways and that you can pick and choose what you want to use.
An application on the other hand (such as a blog or a forum) is already "put together" in a particular way, (usually) provides a graphical user interface and most likely doesn't offer a great deal of integration with your own application.
Embrace the structure of the library and use the components it offers to your advantage. Learning what the components do, rather than blindly copying and pasting existing code will put you in a great position to build a powerful application!