WooCommerce Checkout Field Editor provides you with an interface to add, edit and remove fields shown on your WooCommerce checkout page.
The Advanced Notifications extension for WooCommerce lets you set up order and stock notifications for users other than the admin. These can be used for notifying staff and users of sales, sending stock notices to suppliers, or even sending new orders to drop shippers.
WooCommerce Checkout Field Editor supports several types for custom fields such as text, select, checkboxes and datepickers.
Core fields can also be moved around giving you more control over your checkout without touching the code.