Create and use Hyperlinks and Bookmarks
Hyperlinks are text parts which are embedded into objects - just like in HTML: <a>this is a link</a>. Bookmarks use the same technique, only the objects (see IWPTextObj) have a different object type ObjType.
When the user click on the text which has been marked to be a hyperlink the event OnHyperlink will be triggered. You can now load a different document or locate a bookmark.
Tip: You can use IWPMemo.EnumTextObj to read the url and text of all hyperlinks.
Also see: Example: Convert to HTML