How to add new custom post type in wordpress

add below code in your theme function file

add_action( 'init', 'my_custom_post_type' );

function my_custom_post_type() {
  register_post_type( 'custom_post_type',
    array(
      'labels' => array(
        'name' => __( 'Custom Post Type' ),
        'singular_name' => __( 'Custom Post Type' )
      ),
      'public' => true,
      'has_archive' => true,
	  'supports' => array( 'title', 'editor', 'thumbnail', 'excerpt' )
    )
  );
}