Elias here with Shopify Support. How's it going?
That's a very good question! You can mark a draft order with the payment pending status if you've already sent the invoice and are waiting for the payment. The customer will be able to pay for the original invoice when an order's payment is pending. However, it's worth noting that once an order is marked as pending, you won't be able to edit the order. We've also got a detailed help doc on draft orders and there's a section that breaks down the different statuses when accepting payments for draft orders.
With that said, how are you finding the draft order process?