Mark McLaren has created the following nice video on how to upload a PDF file to your server using Wordpress. And then you can link to the PDF in any of your Wordpress post. Some may not be aware that you can upload PDFs in Wordpress. But you can -- just like you would upload images. In fact, this technique works not only for PDF, but for other documents such as Excel or Word, etc.

This feature is already available in Wordpress without any extra plugins. And you don't need to use any FTP clients.
Although the video is in an older version of Wordpress, this gives an good overview of all the important concepts.