Art question for painters

[nate]

I've been doing some stuff lately for my daughter, and I've had some friends request prints.  I have two questions, for anyone getting their art on:

1: How do I go about getting posters done, of canvas painting?

2: I know there's something you can put on a canvas painting to preserve it for ages, but I honestly have no idea what that is?

Disclaimer: I've used Google, but since I'm kind of a neophyte to this topic, I don't think I'm using the right search terms to get the most of my searching.