Registers an "Invoice" custom post type

invoice-cpt.php

<?php //* Mind this opening PHP tag

/**
 *	Register Invoice Type
 * 
 *	@author     Ren Ventura
 *	@link       http://www.engagewp.com/create-invoices-gravty-forms-wordpress
 */

add_action( 'init', 'rv_invoice_cpt' );
function rv_invoice_cpt() {

	$labels = array(
		'name'					=> _x( 'Invoice', 'post type general name', 'engwp' ),
		'singular_name'			=> _x( 'Invoice', 'post type singular name', 'engwp' ),
		'menu_name'				=> _x( 'Invoices', 'admin menu', 'engwp' ),
		'name_admin_bar'		=> _x( 'Invoice', 'add new on admin bar', 'engwp' ),
		'add_new'				=> _x( 'Add New', 'Invoice', 'engwp' ),
		'add_new_item'			=> __( 'Add New Invoice', 'engwp' ),
		'new_item'				=> __( 'New Invoice', 'engwp' ),
		'edit_item'				=> __( 'Edit Invoice', 'engwp' ),
		'view_item'				=> __( 'View Invoice', 'engwp' ),
		'all_items'				=> __( 'All Invoices', 'engwp' ),
		'search_items'			=> __( 'Search Invoices', 'engwp' ),
		'parent_item_colon'		=> __( 'Parent Invoice:', 'engwp' ),
		'not_found'				=> __( 'No Invoices found.', 'engwp' ),
		'not_found_in_trash'	=> __( 'No Invoices found in Trash.', 'engwp' )
	);

	$args = array(
		'description'			=> __( 'Invoice', 'engwp' ),
		'labels'				=> $labels,
		'supports'				=> array( 'title' ),
		'hierarchical'			=> false,
		'public'				=> true,
		'publicly_queryable'	=> true,
		'query_var'				=> true,
		'rewrite'				=> array( 'slug'				=> 'invoice' ),
		'show_ui'				=> true,
		'menu_icon'				=> 'dashicons-media-spreadsheet',
		'show_in_menu'			=> true,
		'show_in_nav_menus'		=> false,
		'show_in_admin_bar'		=> true,
		// 'menu_position'		=> 5,
		'can_export'			=> true,
		'has_archive'			=> false,
		'exclude_from_search'	=> true,
		'capability_type'		=> 'post',
	);

	register_post_type( 'invoice', $args );

	// Deny access to the post_type query arg
	if ( isset( $_GET['post_type'] ) && $_GET['post_type'] == 'invoice' ) {
		wp_die( 'Unauthorized' );
	}

}