I just wonder whether woocommerce creates a PDF file when an order is placed. I am working on a plugin where I have to attached a PDF invoice to the email. Someone told me it does. I just want to double check.
WooCommerce can send out an email invoice - not a PDF invoice. There's a (paid) extension available if you want to send PDF invoices: https://woocommerce.com/products/pdf-invoices/
We use several time in Woocommerce create PDF Invoice Plugin please check it https://wordpress.org/plugins/woocommerce-pdf-invoices/