The simple way to make a PDF if you are using Microsoft Office™ after 2010 is just to save it as a PDF. If you are using pre-Office 2010, download Apache OpenOffice (http://openoffice.org), install the program, create your PDF, and export as a PDF.
To design it into your website, you can just simply create a link:
<a href=”path/to/your/PDF.pdf” title=”information that describes your PDF”>Visible link to the PDF</a>
UPDATE: Several WordPress plugins now display a PDF just like a web page. If you perform a Google search for WordPress plugins to show PDFs on a website, you should be able to find one that works well. Always check the references and rating when downloading WordPress plugins and always use the WordPress Plugin Repository.