I want to insert into a word document an attachment to other documents so that if someone is reading my document on screen they can click on the attachment to open the other document.

Hi David

The quickest solution would be to set up hyperlinks within your word document that users can click-on to go to the document(s).

These documents could be anywhere on your PC, internal network, intranet or even on the internet.

To create a hyperlink, simply select the word/space in your doument where you want the link, right-click and select "Hyperlink", in the dialog box, paste into the "Address" field the location of your document you want to link to, .
Example - Address: http://www.microsofttraining.net/microsoft-word-training-courses.php

Hope this helps.

Jacob