This payment method is especially still popular in Germany and Austria. This is how it works:
"Payment methods" > "invoice"
Choose the countries in which this payment method should be allowed
Enter a price if your customer should pay an extra fee for using this payment method (not recommended)
Hit "create payment method" and you're done :-)
+payment just after receiving the product and being conent with it
+also possible without online banking
Other payment methods under http://helpcenter.branchbob.com/branchbob-helpcenter-english/activating-payment-methods