Add-ins Overview

You can use add-ins when customizing both your Microsoft Office Outlook form pages and form regions.

COM add-ins   are executable (.exe) files or dynamic-link library (.dll) files that add extra functionality to Outlook.

Using COM add-ins with form regions allows the regions to include custom business logic or advanced functionality. Unlike when you customize form pages in an Outlook form, you do not use Visual Basic Scripting Edition (VBScript) to write code behind a form; instead, you program form regions with a COM add-in. Learn more about extending a form region with add-ins.

Microsoft Exchange Client add-ins   are extension configuration (.ecf) files that add extra functionality to Outlook. These add-ins are installed automatically when you install Outlook. If, for any reason, one of these add-ins is removed, or if you want to use a third-party add-in, you can install it at any time. The following table describes the add-ins available in Outlook.

For more information, see How to: Add or Remove an Add-in.