Edit, Cut, Copy, Paste, and Suggest on Your iPhone
Use the Suggest feature to correct those typos.
Suppose that you notice a typo in what you’ve entered. For example, if you inadvertently typed their instead of there. By tapping Suggest, you can easily make a fix. Upon doing so, the iPhone serves up a few suggested replacement words. If the word you have in mind as a substitute is, um, there, tap it and the iPhone automatically makes the switch.
Another example: Say you inadvertently typed Freek. When you tap Suggest, the iPhone presents alternatives such as Greek, Freak, and Freed.
Meanwhile, if you want to know exactly what a word means, you can double-tap a word and choose the Define option instead. The first time you tap Define, you'll be presented with the option to download the dictionary.