Why is my information not appearing in the export?

WooCommerce added a new feature recently in WooCommerce > Settings > Advanced > Features (the last one). The options are at the very top 'High Performance order storage (recommended)' and 'Enable compatibility mode (synchronizes orders to the posts tables)'.

If these options are not present, it is possible that your WooCommerce is not up to date or that the option has a different name, such as “Enable accounting mode.”

Here is a link to help you https://woocommerce.com/document/high-performance-order-storage/