iFilebox (US$0.99) is a well thought-out addition to your iOS bag of tricks. It lets you create folders, and write notes so you can get organized, and is a nice alternative to Apple's own Notes app.
The app supports passwords on folders, keeping them extra private. Notes can be shared via email and the search function works well. The app does not support Apple's Spotlight search, at least for now, but that would be very valuable to add.
This is a nice and powerful app. You get a lot of choices, like font selection, and notes can be entered with the keyboard of by voice. There is a pretty comprehensive help menu, but it didn't cover deleting folders. Actually the app follows Apple conventions, swiping a folder to the left gives you the option to delete it.
Folders can be designated as favorites for quick access and any note can be bookmarked.
The app is easy to use, and features are generally self-evident. As it is now, the app is not universal, and you need an iPad and an iPhone version, which I don't think presents the best deal for users. The two apps don't sync either, which is the way, I think, people with both devices would want this app to work.
Having said that, iFilebox is very handy, and does a lot that Apple Notes doesn't do. I recommend this app for people who need an organized way to keep notes, and will hope that it will support Spotlight and syncing soon.
At under a dollar, this app can boost your productivity. The app requires iOS 8.1 or later. It's optimized for the iPhone 5.