The system requirements on the official website specify that Jot+ is compatible with Windows operating system and only the following versions: 2000, 2003, XP, and Vista. As you can see, there is nothing related to iOS, Android or Windows phone.
Unfortunately, there is no version of Jot+ for iOS. I've searched on the App Store, but without results. Of course, you can use other alternatives that give you the possibility to create and organize notes.
Send an inquiry to the developers to find out about iOS release: http://kingstairs.com/about/