How do i add SSN/kennitala to an invoice/reciept?

If you are making an invoice and the customer wants to put his or his company SSN/Kennitala on the receipt you must do the following:

First click on the Regarding/Comment box

And in Regarding: you can put the SSN/Kennitala (its good to add kt. in front)

Now you can see in that the SSN/Kennitala is on the invoice so when you print out a receipt it will print on the receipt.