Can I get statistics on which delivery method we use on our customer invoices?

Go to page in InExchange Network: Invoices\Sent invoices

Yes, follow the below steps to receive statistics on this. 

1. Choose a time period. You can also choose what the statistics should contain. You can choose this by clicking Select columns.
   
   
2. Click on Report.

After processing the information the result will be presented in an Excel-document. You can sort the content through customer name, delivery method and so on. 

You can also view the statistics through Start > Overview > Dashboard.