There are two settings here which allow the instance to a) select their invoice layout and b) select whether to allow for thermally printed receipts.
Why we need different formats for invoices?
Each country has its own rules regarding what information should be displayed on an invoice.
OFN has two possible format for invoices today.
1) If the checkbox is left unselected (the default).
This comprises a detail for each line of the price (including OR excluding tax depending on instance set up "prices include tax or not") + the collected tax amount for this line. But the rate applied is not displayed. See an example of the invoice layout below.
2) If the checkbox is selected.
This format that fit more French / European requirements regarding how invoices should be laid out. This comprises a detail for each line of the price excluding and including tax and tax rate applied + a total for the order excluding and including tax and the total tax amount per tax rate that the enterprise need to report to fiscal administration (so if in the order there are items with different tax rates there will be two "total tax" lines in the totals). See an example below.
This option also enable the hub to add some custom text on his hub's invoices (this is done in enterprise setting menu).
Some hubs are using OFN to manage onsite sales and needed to be able to print a receipt with a thermal printer.
By default, when the checkbox is left unselected thermally printed receipts are not printable by enterprises.
If your instance selects the checkbox, your will enable printing of thermal receipts on your instance. The layout of a thermally printed receipt shows each line item and display clearly the amount excluding and including VAT. See the user guide for further details about thermally printed receipts.