Answer to a question that arises: It is the parties who decide how the approval should take place.
This provision is primarily justified by the technical conditions required to be able to receive an electronic invoice and for the recipient to be able to ensure the invoice’s origin, integrity and readability. The recipient’s approval of an electronic invoice can be confirmed in a similar way as when the recipient approves a paper invoice. The confirmation may take the form of a written approval, whether formal or informal, or by implied approval, for example by handling or paying the invoice received. However, this is an issue that the two trading parties may agree on ( see section A 3 of the European Commission’s explanatory notes on invoicing ).
Source: skatteverket.se
