Here is what the main dialog looks like:
[NOTE: I've uploaded what the current dialog looks like. I need to do some fiddling to see if I can get it to access the WordPerfect X3 Address Book, which I do not use.] It allows you to set up one or more custom envelope templates, including the custom fonts, graphics, spacing, whatever you want, and uses the template to generate the envelope.
In addition, for those using InfoCentral, the dialog will import addresses from InfoCentral or the Address Book, and export addresses to either one (including telephone numbers and e-mail address), meaning it will work as an import/export utility.
The utility comes with a mini-manual ("Envelope.wpd") with instructions on how to use it (it's actually really simple), including a hyperlinked Table of Contents.