Need to save a word document received on email to my iPad 2

You need an app like GoodReader to save the mail attachment. When you touch and hold an emial attachment there is be options for where you can open the attachement. An app like GoodReader will open and also save attachments.

You will first need an app on the iPad that supports word documents - unlike a 'normal' computer the iPad doesn't have a file system, and everything on it has to be associated with an app. Apps that support word documents include Apple's Page app, and third-party apps such as Documents To Go and QuickOffice Pro HD - when you have an app you should then be able to use 'open in' on the email to save the document to that app.