Inkwell, more commonly known as Ink, is a handwriting recognition tool, built-in to OS X. You can use it in most applications which allow text input, and for the most part, Ink is very accurate. In order to use Ink, you'll need a graphics tablet.
Activation and Setup
Once you've plugged in and installed your graphics tablet's drivers and software, you'll see a new icon appear in System Preferences, labelled Ink.
Click the icon, and switch Handwriting Recognition into the On position.
Now, set the width of your handwriting, your pen's options, the font, the language, the gestures, and the word list to how you'd like them to be.
You may also wish to alter how quickly recognition begins after lifting the pen. This can be done by clicking the Options button, in the bottom-right corner of the main window.
Using Inkwell With Pages
Inkwell works in almost any application which allows the user to input text. In this example, I'll be using Pages, though the process is much the same for most applications.
Open up Pages, and create a New Document.
In the small window, labelled Ink, ensure that the Pen tool is in use. You can tell which mode is in use by the icon. If there is an icon of a Pen, then the Pen tool is in use. If you see a Mouse Pointer icon, you should click the icon and see the Pen icon appear.
Now, you can either begin writing with your graphics tablet directly onto the document, or onto the small Ink Pad. I recommend using the Ink Pad, as it provides a smaller, but more focussed writing space. Click the Ink Pad icon, resize the window, and begin writing on the pad.
The text will be added to the document, after every few characters you write.
You've now learned how to use Ink on a Mac. You began by enabling Handwriting Recognition in System Preferences, set everything up, and then created a new document in Pages and began writing.
If you have any questions, please leave a comment below and I'll be sure to get back to you.