You can use register_post_type to add a custom post type to your theme. However, you must use this function in the init action of your theme. Otherwise, it will not work. It is best to use this function in a plugin to avoid losing the custom post type with theme updates. To get started with register_post_type, you can follow these steps. Listed below are some useful tips for setting up custom post types:
First, you must specify the post type name. If you are adding a custom post type to your theme, you must specify the name. This name is also known as the slug. It is recommended that you use a short name for your custom post type. The slug is also important because it can be confusing for your visitors. This function lets you change this field using PHP code. It is also useful if you want to add an archive page to a specific post type.
Another useful function is register_post_type. This function registers different types of posts in WordPress. WordPress comes with built-in post types, but users can add their own. A custom post type is defined by specifying a key and argument. You can define characteristics and behavior of your new post type with the post_type_arguments function. Once you have registered a new post type, it will appear in the admin area of your site.