Marion Maureen Fellows wrote:
How do I create a universal amazon link?
If you're talking about creating a hyperlink, then technically you can't, as there isn't a universal A'zon.
A'zon is broken down into various sites, such as .com. .co.uk, .ca etc. If you're looking to provide people with a link, say to your book, you need to do one per site, for as many sites as you think are relevant.
If you need advice on how to actually create a hyperlink, then Go*gle is your friend.