Dropzone does not provide the server side implementation of handling the files. I can't stress this enough, so let's repeat it:
The way files are uploaded is identical to a standard file upload with a standard HTML form like this:
<form action="" method="post" enctype="multipart/form-data"><input type="file" name="file" /></form>
So if your server accepts files, uploaded like this, it will accept files uploaded with Dropzone.
So please look at the corresponding documentation of the server implementation you're using. Here are a few documentations, if you think I should add some, please contact me.
Complete PHP tutorial by startutorial.com
Tutorial for Dropzone and Lavarel (PHP) written by Maksim Surguy
eBook for Dropzone with PHP by startutorial.com.
Please look at the Dropzone FAQ if you need more information.