If you are new to WordPress then you may be wondering how the design works and what WordPress Themes are.
From the WordPress website:
Fundamentally, the WordPress Theme system is a way to “skin” your WordPress site. Yet, it is more than just a “skin”. Skinning your site implies that only the design is changed. WordPress Themes can provide much more control over the visual presentation of your content and other data on your WordPress site, as well as behavior of certain site’s elements while interacting with visitors.
A WordPress Theme is a collection of files that work together to produce a graphical interface with an underlying unifying design for a website. These files are called template files. A Theme modifies the way the site is displayed, without modifying the underlying software. Themes may include customized template files, image files (*.jpg, *.png, .gif), style sheets (.css), custom Pages, as well as any necessary code files (*.php).
So basically a theme is not only a design for your website but can also enhance the site by providing extra functionality. WordPress comes with a default theme (since 2010 there has been a new one each year named after the year in question, currently we are at Twenty Nineteen) to get you started and there are thousands more free and paid-for themes available.
Once uploaded you can them customise your theme to how you want it or even create your own. For more information on themes, visit the WordPress Codex or contact me to discuss how WordPress can help your business.