RSForm!Pro allows you to send custom emails (user and admin emails) after the form submission.
These two types of email are configured separately in the "Manage forms" area, when editing a form, in two corresponding tabs ("User Emails" and "Admin Emails").
This video tutorial explains how to configure the user and the admin email.
We have created a Joomla! form with 5 components: 2 textboxes for the fullname and email, a textarea for the message and a radio group with 2 options "Yes" and "No"(users are receiving a file attachement if this option is set to "Yes").
In the last part of the tutorial, we've included a custom PHP code in the "Email scripts" tab, that allows you to send the user email with a file attachment.