Themes are add-ons for WordPress that change the way your site looks. They let you choose a custom appearance for your blog.
WordPress comes with a few basic themes when you install it on your website. But there are thousands and thousands of themes out there that you may use.
To search for free themes just click Appearance on the left menu of the admin dashboard, then click Themes. You’ll see many listed right away and you may browse those themes and install any of them to try out.
There are also paid themes. Paid themes tend to be more supported and are often more reliable. They may also have periodic security updates and fixes released by the theme developer. When you pay for a theme you support the developer who created the theme and they are able to give you more support too.
I recommend paid themes that use the Genesis framework. A framework is a fancy way of saying that the underlying code is designed so it can be updated regularly without messing up how your site looks. When you have a Genesis theme the framework get updates once or twice per year which helps protect your blog’s overall security and helps keep it current for search engines, too.