Custom Taxonomies are same like categories and tags. WordPress allows developers to create Custom Taxonomies. Custom Taxonomies are useful when one wants to create distinct naming systems and make them accessible behind the scenes in a predictable way.

Create Custom Taxonomies by code.

Add below Code in function.php file of your active child theme (or active theme).

1. Creating a Hierarchical Taxonomy
First we create hierarchical taxonomy that works like categories and can have parent and child terms. Add the following code in your theme’s functions.php file or in a site-specific plugin (recommended) to create a hierarchical custom taxonomy like categories:

2. Creating a Non-hierarchical Taxonomy
Create a non-hierarchical custom taxonomy like Tags, add this code in your theme’s functions.php or in a site-specific plugin: