A theme is a preset package containing graphical appearance details, used to customize the look and feel of home page of the website. Theme is used to change the site wide appearance of a whole range of things at once, like buttons, color, layout, text, logo, background amongst others.
They provide your website a total new vibrant look which can act as an attraction to the members of your website. It also prevents the boredom a website attaches to itself when it possesses the same look for a longer period of time. You can also enliven your members by providing them different kinds of themes related to ongoing scenarios like product, service, affiliate, seasons, festivals, worldwide important days, historic events or some bigger world news.
In Themes menu, you can change the default theme of your website. You can choose from various in-built themes or from the themes that have been uploaded.
Go to Admin control panel – Themes
The menu shows:-
To learn how to create your own themes, read Create Themes.