Is there any way of viewing PDF and docx files on this tablet

Adobe Reader for PDFs and if you type docx into Google Play there are plenty of readers for them.

Download Quickoffice from Google Play.

It's developed by Google and reads Word, Excel and Powerpoint as well as PDFs. You can also create new documents from it and it's free. I really find it useful.

Seconded for Quickoffice, a guality office suite app

Why not start using Google Drive? That will open everything you need, and we use it for business so can vouch for how reliable it is. Quick Office works seamlessly with Google Drive too should you wish to use that with it.

Mark