"To" é para quem; o recipiente do correio, presente, articulo, ecetera "From" é de parte de quem; a pessoa que está enviando/mandando o correio, presente, articulo, etc

From: http://www.englishandculture.com/blog/bid/95563/Quick-English-Grammar-Tip-To-Versus-For Follow the link for examples. Use "to" when there is some kind of transfer happening or something is being moved from one place to another. 1) Use "for" when something is being done to benefit something or someone else. 2) Use "for" when you are trying to express purpose or the reason that something is happening