A policy that lives in email is not a controlled document. A library is the place that says which version is current, who manages it, and when it is next due for review.
What you need to be able to show
How document management helps describes the product.
- The current version, and the history of the versions before it.
- The status of the document, such as draft, in review, or published.
- Who manages it, and when the next review falls.
- How the document relates to the clauses it is meant to meet.