Setting Default Payment Methods allows you to either Mark ALL Invoices for that supplier as paid from within company settings or enables selecting individual invoices as paid from within the inbox. Setting the Payment methods here does not publish an invoice as paid until 'Mark as Paid' is selected. To set up payment method defaults for a supplier, Payment Accounts must first be set in Company Settings here.
To Set the default payment method simply select the desired account the payment is coming from
And the account the invoice is to be published to.
Some accounts packages also require a Payment Method to be selected in which case a third menu will appear:
All selections are automatically saved.