How do I add my son's name to the deed of my property

This is almost a trick question because if you know how it is very easy, but if you don't know how you can really mess it all up.

So best bet decide first why you want to, next know the risks, if the son gets a large debt, or goes bankrupt it is putting your property at risk,
While you can also merely put him in a will to get the property.

But if you want to add him, get a title company or a real estate attorney to do it for you.