Outlook has a number of standard forms you interact with, and they're all specific to the task you're trying to complete. But with all of Outlook's views, it can be difficult to find just the right form. Even if you know exactly how to display the form, sometimes, it's just inconvenient to do so.
For instance, suppose you're in the middle of writing an important e-mail message and you remember that you meant to log something in your journal but forgot. You could switch to Journal view and open a new Journal Entry form by clicking the New button or by pressing Ctrl+N, but you don't have to. With the e-mail message still current, simply choose Forms from the Tools menu and then select the Choose Forms item. The Standard Forms Library is the default, and Journal Entry is in that library. (If you're looking for a form that isn't in the Standard Forms Library, choose another library from the Look In control's drop-down list.) Select Journal Entry in the Choose Forms dialog box, and click Open. When you finish making your entry, save and close it, and you're right back in your e-mail window.
Having all the forms available in most any view lends a great deal of flexibility. The interruption to your current task is much less intrusive than switching between views and more easily completed.