The advantage with Sticky Notes is that it autosaves – but then Notepad opens faster and simpler. However, for quick access, both of them should be either on the Desktop or the Taskbar.

Download the Sticky Widgets app from the App Store to add sticky notes to your iPhone's home screen. Add the widget by ...

and close that note window when not needed. There exist some good free third-party sticky notes tools that show only one taskbar icon no matter how many notes are created or opened. Even if ...