Press Kits
You should use folders that either allow you to remove the front cover to insert in your printer so you can put it through your printer and print your book cover on it, or the folders that have a pocket on the front cover that allows you to insert a 8 1/2 x 11 piece of paper in it. All you do, then, is print your book cover on the 8 1/2 x 11 paper and insert.
And here's what actually goes inside the press kit:
