Notes is a notetaking app developed by Apple Inc provided on the company's iOS, iPadOS, visionOS, and macOS operating systems, the latter starting with OS X Mountain Lion.

The application uses a similar interface on iOS and macOS, with a non-textured paper background for notes and light yellow icons, suggesting pencil or crayon.

Until 2013, both applications used a strongly skeuomorphic interface, with a lined, textured paper design; the Mountain Lion version placed this inside a leather folder.

In iOS 7, as with all other default apps, Notes was redesigned, losing the notepad like UI in the process.

Starting with iOS 9, Notes received a significant functional overhaul: iCloud sync (instead of IMAP; in-line with the OS X El Capitan version), the ability to create sketches (and later, support for Apple Pencil), advanced text formatting options, several styles of lists, rich web and map link previews, support for more file type attachments, a corresponding dedicated attachment browser and a system share extension point for saving web links, images, etc.

This situation was a kludge: as Apple Mail already implemented the IMAP mailbox synchronization protocol, it could also sync notes with minimal additional work.

As of OS X El Capitan, Notes received a significant functional overhaul (in-line with the iOS 9 version), with major features including: iCloud sync, the ability to view sketches created on the iOS counterpart, advanced text formatting options, several styles of lists, rich web and map link previews, support for more file type attachments, a corresponding dedicated attachment browser and a system share extension point for saving web links, images, etc.

[15] As of OS X El Capitan 4, individual notes can be password-protected, with the password syncing across compatible devices.