Evernote just feels like it has been around forever so it probably has! It is one of those staple apps with a massive following. It's not a pretty app but it is definitely practical. Evernote is a supernote and organiser tool that works on (1) the web, (2) on PC/Mac desktop apps and (3) on mobile apps so basically you can get Evernote everywhere. Notes are stored in notebooks in the Evernote Cloud.
Free for the next few days. Normally about £4.99. You should grab it while it is free just for a try.
http://www.educatorstechnology.com/2014/05/a-great-mindmapping-and-notetaking-ipad.html