RTF Action
The standard RTF action process your document quickly with all properties set within the form design. Simple give your action a name, browse for your document, the add the fields to the proper location in the document, optionally you can add scripting before the action and after the action is run. As well to hide this action check the "Hidden Action" checkbox. Once you've completed these steps click "Save" to save your action.

Clicking the "Add Word Fields" button will open your selected document, hide the Creator, and load the field inserter interface.
Simple position the cursor in your document where you would like the field inserted and double click the field on the RTF Field inserter. You can also easily drag and drop the field desired to your RTF document as well.