WordPress Conditionals are functions that allow you to more specifically execute your code in WordPress. So for the web developer this means that you can, for example, add_action a custom banner ad right before your posts, but let’s say ONLY on the front-page of your website. This would be done using the is_front_page() conditional tag like so:
Note that I provided several examples in the above code snippet, each providing either the same or similar results, but just using different methods to show various solutions. Also note that the last example went a bit further by adding the || (which stands for OR in PHP) operator to allow execution if it’s the front page of the site OR a single page. This gets us into logical operators which I won’t be covering anymore here, but you can read more about them HERE.