Klarna can be integrated with a Shopify store via multiple integration methods. We recommend that only one of the following integration methods is active in the checkout:

A direct, additional payment method, for all Klarna payments regions, supported by Klarna.

• Klarna as an alternative payment method on Shopify is available using Shopify's new payments app integration.
• To integrate Klarna as an alternative payment method with your store, please follow the integration steps from Klarna.Docs.
• Klarna as an alternative payment method can only be used by customers whose billing address matches the Shopify base currency. Read more about multi-currency payments on Klarna.Docs.
• See the list of regions supported by Klarna.

• Klarna can be added as a local payment method (Sweden, Germany, Austria, United Kingdom, Netherlands, Spain and Italy) and supported by Shopify.
• Read more about adding Klarna as a local payment method on Shopify documentation.

Klarna can be enabled through other integrations, based on region, such as Mollie, Global-e, and others. Shopify documentation lists available payment options by region, for example, in Sweden, and each of these is supported by the integrator.

To check which Klarna integration is active in your store, go to your Shopify admin > Settings > Payments to review your store's active payment methods.

You can also review the names of Klarna payment methods in your store's checkout. Refer to the translated list of supported Klarna payment methods.
If Klarna is listed multiple times in checkout (for example, as Pay now with Klarna, Pay later with Klarna, and Finance with Klarna), the integration isn't supported directly by Klarna, but rather supported by the integrating partner.

Integrating and using Klarna as an alternative payment method requires an active Klarna account. If you don’t have one yet, you can sign up at http://klarna.com/business. 

Once Klarna has been successfully integrated, you can make use of the Klarna On-site messaging app, available for free in the Shopify app store.

In summary:

• Klarna can be integrated into a Shopify store in different ways, such as additional payment method, local payment method, and other integrations based on region like Mollie or Global-e. 
• Checking the active Klarna integration in the store is possible through Shopify admin > Settings. 
• A successful integration enables the free use of the Klarna On-Site Messaging app.