Since the contents of a WordPress site is contained within a Database and not statically within a piece of content, the appearance of the site can be modified independently. This is controlled through the Appearance menu within the WordPress Admin area. Hovering over Appearance will bring up multiple sub menu items. Let's look at Theme.
Themes are where the main components driving the appearance are contained. As we can see this site has a single theme installed, Twenty Twenty One.
Themes are available through the WordPress Repository or third party theme developer sites. For this training we will focus largely on those freely available in the Repository.