Go to the orders page from the WooCommerce menu bar. Where you can see the document column on the orders list table from there you can access documents. Also more controls in individual order details page like creating the invoice, access credit notes, order tracking number meta box and invoice number details, etc.
Click on individual document icons for accessing the document.
Click on the particular order to see its details and documents associate with it.
You can click document buttons for accessing it. Also you can adjust value of order tracking number meta box.