If you find that you frequently type the same text on a regular basis, there’s a handy feature hidden away in the iOS Settings app that can save you a lot of time. If you take a trip into Settings, General, Keyboard you’ll find a section labelled “Shortcuts” where you can add your own abbreviations that will automatically expand into any larger phrase that you would like. While it’s not without a few limitations—multi-line text isn’t supported, for example—it’s definitely a really useful feature, especially on the iPhone and iPod touch keyboard.
Once you’ve created your shortcuts, simply type in the abbreviation and it will be automatically expanded, auto-correct style, to the full phrase. Not only can this be used for common phrases like “On my way” but is also great for things like you’re email address or longer logon names used for online services, since this replacement feature works in just about any text field throughout iOS. It can also be used to override phrases and spellings that auto-correct frequently gets wrong—simply enter the exact same text in the “Phrase” and “Shortcut” fields and this will override the normal auto-correct lookup when typing that word in.