Klarna allows customers to pay for their goods online without having to enter any personal details. Instead, they can pay with a one-click checkout system. This process allows you to sell more goods, as customers are less likely to abandon their shopping carts and leave your site if they don't have to input sensitive information. It also reduces the risk of fraud; since Klarna doesn't require any personal information from the customer, it's impossible for them to make fraudulent purchases using stolen credit cards or other means.

Klarna was founded in 2005 by Sebastian Siemiatkowski and Niklas Adelgren, who were inspired by the "buy now, pay later" service offered by American companies such as PayPal. They soon developed a similar service for European customers, which required no registration or credit check—and instead allowed consumers to pay later after they received their goods or services.

Klarna has now become one of Europe's largest e-commerce companies; they are available in over 30 countries worldwide and process over 5 million orders per month. They have also expanded into other markets beyond payments—for example, offering insurance services through partnerships with companies like Mastercard and Visa.

Klarna offers two main products: Klarna Credit, which lets customers buy something immediately and pay it off over time; and Klarna Invoice, which allows sellers to collect payments from buyers directly on their website.

If you're an online merchant and want to use Klarna's products in your store, you'll need to sign up for an account with them first. Once you've done that, they'll give you access to their tools where you can create an invoice template or choose from one of theirs. You can then add this invoice link on your website where customers will see it when they check out—they'll click on the link and be brought to a page where they can pay using their credit card information or other payment option if applicable (like PayPal).