additional to shopify payment I am also offering payment by invoice. This service ist provided by "Klarna" and conected through an app.
Unfortunatelly this service is quite high in fees. So rather than changing my product prices I would add this extra fee in the checkout process only for those who select this specific payment option. How can I do this? I already talked to the payment provider, they don't offer an option to include this.
So I would need some automation that adds the fee of XY € or XY % of sum if payment option "invoice" is selected,.