How to Add Custom Code to WordPress

There are many books and tutorials that share useful code snippets for WordPress. For example, you can find hundreds of custom functions right here at DigWP.com. You can also find them in my WordPress books, tutorials, and code snippets. For many code snippets and custom functions, the usage instructions will say something like:

Add this code to your theme (or child theme’s) functions.php file, or add the code via simple custom plugin.

So what does that actually mean? Let’s take a closer look. First we’ll go through how to add custom code via the functions.php file. Then we’ll explain