This plugin integrates WooCommerce with Fortnox. Automating your accounting and inventory.
It can create a Fortnox Invoice or Order based on a WooCommerce Order.
Customer data will be stored in the Fortnox customer database and will be automatically updated if changed in a new order.
Invoices can automatically be set to paid based on the payment method used in the WooCommerce order.
The plugin can create internal invoices and voucher to automate the handling of payouts for a number of payment gateways.
You can find detailed installation and configuration instructions
here