The order has payment method "Terms", why is that? 

@market online allows Buyers to place orders on terms.

For orders where the payment method is terms, it is your task as a Seller to reach out to the Buyer to establish a method of payment.

For buyers who have yet to be associated as a customer, the terms on the order may show as "Terms".

Once you have approved the order, you are given the opportunity to associate the Buyer to an existing customer or create a new customer and then establish terms. Every future order after establishing terms will now have the appropriate terms however this first order will remain “Terms"

When creating an invoice for orders with Terms as payment method, you will have to manually mark the invoice as “Paid” once the Buyer has paid, to change the status.  

Please note, you must work with the buyer to figure out a method of payment outside of @market online.
For example, you could coordinate a check / money order or an electronic invoice through your accounting or payment processing software.