Klarna payment method is available for restaurant accounts with Stripe direct integration enabled. 

Klarna can be used at the checkout by food clients in the following countries: Austria, Belgium, Denmark, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Lithuania, Netherlands, Norway, Slovakia, Slovenia, Spain, Sweden, United Kingdom, United States.

To enable it, make sure that the restaurant has enabled the Online payments service and has connected a merchant account from Stripe. Then go to the Stripe account -> Settings -> Payment methods and turn it on, like this:

Then return to the restaurant admin panel and enable Klarna: 

Make sure the currency set up in the admin panel is the official currency of the country where the restaurant is located.

This is how the food client sees Klarna payment method at checkout:

After selecting Klarna as a payment method and Continue, food clients will be redirected to the Klarna payment page.