This documentation refered to the former WooCommerce Helper plugin, available as a separate plugin up to WooCommerce 3.0.x. This plugin and the versions of the core WooCommerce that use it are unsupported by the WooCommerce.com support team. As such, this documentation is no longer being updated.
Note: The WooCommerce Helper plugin was merged into the core WooCommerce plugin as of version 3.1. Purchase, connect, download products, and activate keys in one place with ease. Read more at Managing WooCommerce.com subscriptions.