http://www.fonerbooks.com/print.htm This guy knows what he is doing. He uses power point to design book covers. I downloaded free Open Office and started a 3 column document: back, spine, front. I typed up a 12 inch wide by 9 inch tall cover that would wrap around the whole book, or maybe be a dust cover. There are lots of settings to play with to get it right. PDF is tricky and measurements should be exact to get the cover perfect. Publishers require embedded fonts, etc. Probably many other ways to do this. I don’t know if this is the best or even acceptable but it just took a few minutes. I would check to make sure the software can do exactly what the publisher requires before putting much work into it.