Word Processing apps with Dropbox integration

Hi all, this is my first post as I've only just joined the Applevis community though I've been using iDevices for over 2 years! I'm looking for an app that will allow me to open a Word or other Office document from Dropbox, edit it and then save it back to Dropbox to access elsewhere. I could do with being able to increase font sizes if needed. Some of the documents I access regularly and might want to add to are Word docs that have password protection, so the app would need to be able to let me input the password to access those too. I'm not a regular VoiceOver user, so accessibility is not essential, but a nice clear and simple visual style is more important to me. I would be using the app on my iPhone 5 with iOS 7 and iPad 3 with retina display also with iOS 7. Any suggestions would be much appreciated. Thanks, Neana