Klarna Payments can be enabled quickly with a few configurations.
Navigate to: Stores ⇒ Configuration ⇒ Sales ⇒ Payment Methods ⇒ Klarna ⇒ Klarna Payments
Make sure you have your API credentials set up. More info here
1. Expand the Klarna Payments section and set Enable to Yes.
2. Set Allowed Countries to one of the following:
All Allowed Countries = Customers from all countries specified in your store configuration can use this payment method.
Specific Countries = After you choose this option, the Payment from Specific Countries list appears. You can select multiple countries.
3. If your Klarna account supports B2B payments, set Enable B2B to Yes. Note: With B2B enabled, since there is not currently a supported selector for customers to set the order as B2C (business to consumer) or B2B, when a customer enters data into the 'Company Name' field, the order will be set as B2B.
Your Merchant ID has to be enabled for B2B by Klarna (available currently only is some regions).
4. If you want Klarna to prepare a set of personalized credit options for each customer, set Enable Data sharing to Yes and set Enable Data sharing on load to one of the following:
No = Customer billing and shipping address information is shared with Klarna after the transaction is authorized. If a shipping address error is encountered during authorization, the customer is instructed to return to the previous step and correct the problem.
Yes = Customer billing and shipping address information is shared with Klarna when the payment method is selected during the checkout process.
5. If you offer multiple payment methods, enter a number for Sort Order to determine the sequence in which Klarna appears when listed with the other payment methods.