You can design a simple book cover using Adobe Illustrator or Photoshop, a word processor with photo editing capabilities or an online publishing company's cover creation service. The software must have the ability to enter text of different sizes, fonts and colors over an edited image or background.
There are a few key factors to consider when creating a book cover. For example, the title text should be large enough to be visible in a thumbnail image for online distribution. Any wording on the cover must be congruent with the art or photography. It's best to focus on a single all-encompassing visual, as opposed to trying to create several images to illustrate multiple themes or topics within the book. You can create your own image or purchase one online.
The back cover is as important as the front cover and can be easier to design because it does not necessarily need an image. It is generally not a good idea to stretch an image on the front to the back; this can distort the image. Write a blurb with a teaser about the story or explanation of the topic and include short recommendations from other authors or media sources, if you have any.