You can do that with UltimateWB. It is a great website builder. It has lots of built-in apps including a files app that you can use and customize to allow users to upload files, documents, and pdfs. It is very easy to use. You can design your own website style with the built-in styles manager. It comes with a built-in seo tool too.
Got a techy/website question? Whether it’s about UltimateWB or another website builder, web hosting, or other aspects of websites, just send in your question in the “Ask David!” form. We will email you when the answer is posted on the UltimateWB “Ask David!” section.