Apple's notes app is great, but one thing it lacks is an option to see when a note was created; it only shows the last modification date. NotesCreationDate solves this problem and lets you see both dates.
NotesCreationDate currently only works with iCloud and 'On My iPhone' accounts. Support for other accounts might be added in the future. If you are a developer and want to help make it happen, the source code is available on GitHub.