iPhone storage/sharing

I have accounts with Dropbox and Evernote that I never set up, I have never used before and need to find out how to track down to close out. I have nothing on my iPhone for these two accounts, absolutely no where from Home Screen to Apps to Settings, just confirmations that 1. They are receiving my info and 2. I am sender and accounts are in my name. How do I locate to close and then remove from my iPhone permanently? Thanks